CDECK  ID>, INFORM. 

                           H E R W I G

            a Monte Carlo event generator for simulating
        +---------------------------------------------------+
        | Hadron Emission Reactions With Interfering Gluons |
        +---------------------------------------------------+
      G. Marchesini, Dipartimento di Fisica, Universita di Milano
          I.G. Knowles(*), M.H. Seymour(+) and  B.R. Webber,
                   Cavendish Laboratory, Cambridge
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 with Deep Inelastic Scattering and Heavy Flavour Electroproduction by
 G.Abbiendi and L.Stanco, Dipartimento di Fisica, Universita di Padova
-----------------------------------------------------------------------
        and Jet Photoproduction in Lepton-Hadron Collisions
             by J. Chyla, Institute of Physics, Prague
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(*)present address: Dept of Physics and Astronomy,University of Glasgow
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(+)present address: Dept of Theoretical Physics, University of Lund.
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                     Version 5.8 - August 1994
-----------------------------------------------------------------------
 Main reference:
    G.Marchesini,  B.R.Webber,  G.Abbiendi,  I.G.Knowles,  M.H.Seymour,
    and L.Stanco, Computer Physics Communications 67 (1992) 465.
-----------------------------------------------------------------------
 Please send e-mail about  this program  to one of the  authors at the
 following addresses:
       Decnet   : 19616::webber, vxdesy::abbiendi, 19800::knowles
       Internet : webber@hep.phy.cam.ac.uk,
                  mike@thep.lu.se, knowles@v2.ph.gla.ac.uk
-----------------------------------------------------------------------

                        ******CONTENTS******

    1. INTRODUCTION
    2. NEW FEATURES OF THIS VERSION
    3. FEATURES NOT YET INCLUDED
    4. PROGRAM STRUCTURE
    5. BEAMS AND PROCESSES
    6. INPUT PARAMETERS
    7. COMMON BLOCK FILE
    8. FORM FACTOR FILE
    9. EVENT DATA
   10. STATUS CODES
   11. EVENT WEIGHTS
   12. HEAVY FLAVOUR DECAYS
   13. QCD HARD SUBPROCESSES
   14. DIRECT PHOTON SUBPROCESSES
   15. QCD HIGGS PLUS JET SUBPROCESSES
   16. ELECTROWEAK SUBPROCESSES
   17. INCLUDING NEW SUBPROCESSES
   18. ERROR CONDITIONS
   19. SAMPLE OUTPUT
   20. GUIDE TO SAMPLE OUTPUT
   21. SUBROUTINE DESCRIPTIONS

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                     ****** 1. INTRODUCTION*******

    HERWIG is a general-purpose event generator for high energy hadronic
    processes,  with particular  emphasis on the detailed  simulation of
    QCD parton showers.  The program has the following special features:

  * Simulation  of any  combination of  hard lepton,  hadron  or  photon
    scattering and soft hadron-hadron collisions in one package.

  * Colour coherence of partons (initial and final) in hard subprocesses

  * Heavy flavour hadron production and decay with QCD coherence effects

  * QCD jet evolution  with soft gluon interference via angular ordering

  * Backward  evolution of  initial-state partons including interference

  * Azimuthal correlations  within and  between jets due to interference

  * Azimuthal correlations  within  jets  due  to   gluon   polarization

  * Cluster  hadronization of jets via  non-perturbative gluon splitting

  * A similar  cluster  model for soft and  underlying  hadronic  events

   Further details may be found in the references cited above and at the
   end of this Section, and in comments distributed throughout the code.

   The program  operates by  setting up  parameters in common blocks and
   then  calling a  sequence of  subroutines to generate an event. Para-
   meters  not set in the main program  HWIGPR are set to default values
   in the main initialisation routine HWIGIN.

   To generate events the user must first set up the beam particle names
   PART1, PART2 (type CHARACTER*4) in the common block /HWBEAM/, and the
   beam momenta  PBEAM1, PBEAM2 (in GeV/c), a process code IPROC and the
   number of events required  MAXEV  in /HWPROC/.  See Sect. 5 for beams
   and processes available.

   All  analysis of  generated  events  (histogramming, etc.)  should be
   performed  by  the  user-provided  routines  HWABEG  (to initialise),
   HWANAL (to analyse an event) and  HWAEND  (to terminate).  At present
   HWANAL  writes  event  information and stable  particle  data on unit
   LWEVT  defined in  HWIGIN (or simply returns if LWEVT=0).  See HWANAL
   for details of event information written.  Note  that  HWANAL  should
   always begin with the line
      IF (IERROR.NE.0) RETURN
   to prevent it being executed for incomplete events.

   A detailed  event  summary is printed out for the first  MAXPR events
   (default MAXPR=1). Set  IPRINT=2  to list the particle identity codes
   and  (simplified) particle decay schemes used in the program.

   The  programming language is  standard Fortran 77 as far as possible.
   However,  the  following  may  require  modification  for  running on
   computers  other than  Vax's:

  *  Most  common  blocks are  inserted  by  INCLUDE 'HERWIG58.INC'  Vax
     Fortran  statements   (see  below  for  contents  of  HERWIG58.INC)

  *  Subroutine  HWUTIM (returning CPU time left) is  machine dependent.

    The principal references are:

    G.Marchesini  and  B.R.Webber,  Nucl. Phys. B310 (1988) 461;  I.G.
    Knowles,  Nucl. Phys. B310 (1988) 571;  S.Catani, G.Marchesini and
    B.R.Webber, Nucl. Phys. B349 (1991) 635;  G.Abbiendi and L.Stanco,
    Comp.Phys.Comm. 66 (1991) 16, Zeit. Phys. C51 (1991) 81;
    M.H.Seymour, Zeit. Phys. C56 (1992) 161.

    Some additional relevant references are:

    A.Bassetto, M.Ciafaloni and G.Marchesini, Phys. Rep. 100 (1983) 201;
    G. Marchesini  and  B.R. Webber,  Nucl. Phys.  B238 (1984) 1;  Phys.
    Rev. D38 (1988) 3419;  B. R. Webber,   Nucl. Phys.  B238 (1984) 492;
    Ann. Rev. Nucl. Part. Sci. 36 (1986) 253;  I.G. Knowles, Nucl. Phys.
    B304 (1988) 794; Computer Phys. Comm. 58 (1990) 271.
 -----------------------------------------------------------------------

                 *** 2. NEW FEATURES OF THIS VERSION ***

  * A hard matrix element correction has been introduced in DIS (IPROC =
    90**).  This is switched  on and  off by the logical variable HARDME
    (default = .TRUE.).  The method is essentially identical to the e+e-
    correction,  generating  first  order  matrix-element  events  in  a
    phase-space region  complementary  to that of the parton shower. The
    e+e- correction is also now controlled by HARDME for consistency.

  * Soft matrix element corrections have been introduced in DIS and e+e-
    processes.  These correct  the distribution of emissions  within the
    parton  shower  phase-space.   It is similar to  the method  used in
    JETSET,  except that the  HARDEST emission is matched to the leading
    order matrix element, not the first as in JETSET.  This ensures that
    the correction  enters into the  form factor,  and not just the real
    emission probability.

  * In the backward evolution of initial-state radiation for photons the
    anomalous branching q-qbar <-- gamma has been introduced.

  * The treatment of forced branching of gluons and sea (anti-)quarks in
    backward evolution has been improved,   by allowing it to occur at a
    random scale  between the space-like cutoff  QSPAC  and the infrared
    cutoff, instead of exactly at QSPAC as before.
    A new option  ISPAC=2  allows the freezing of structure functions at
    the scale QSPAC,   while evolution continues to the infrared cutoff.
    The default,  ISPAC=0  is equivalent to previous versions,  in which
    perturbative evolution stops at QSPAC.

  * It is now possible to completely switch off initial-state radiation,
    by setting NOSPAC =.TRUE.   Only the forced splitting of non-valence
    partons is generated. The default is (of course) NOSPAC =.FALSE.

  * An option to damp the parton distributions of off mass-shell photons
    relative on-shell photons,  according to the scheme defined in Drees
    and Godbole MAD/PH/819 has been introduced. The adjustable parameter
    PHOMAS defines the crossover from the  non-suppressed to  suppressed
    regimes.  Recommended values lie in the range  QCDLAM to 1 GeV.  The
    default value PHOMAS=0. corresponds to no suppression as in previous
    versions.

  * The interface to PDFLIB version 4 has been slightly changed. Instead
    of indicating a PDF set by a unique number, an `author group' string
    and set number are required. PDFLIB version 3 can still be used from
    HERWIG, simply by setting the author group to 'MODE'. It is also now
    possible to independently set the PDF set for each of the two beams.
    For example, if you previously used MRS D- for the proton and Gordon
    -Storrow set 1 for the photon, by setting
          MODPDF=47
          MODPHO=231
    You should now set
          AUTPDF(2)='MRS'
          MODPDF(2)=28
          AUTPDF(1)='GS'
          MODPDF(1)=2
    Alternatively, if you are still using PDFLIB version 3, you can set
          AUTPDF(2)='MODE'
          MODPDF(2)=47
          AUTPDF(1)='MODE'
          MODPDF(1)=231

  * In the  CLDIR=1  option for  cluster  decays  a new parameter  CLSMR
    (default = 0.)  allows a  Gaussian smearing  of the direction of the
    perturbative quark's momentum.  The smearing is actually exponential
    in 1-cos(theta) with mean CLSMR.  Thus increasing CLSMR decorrelates
    the cluster decay from the initial quark direction.

  * New subprocess have been added:

    - The direct,  higher twist,  production of light (u,d,s) L=0 mesons
      by point-like photons is now available: IPROC = 5500 all Spin =0,1
      mesons, = 5510 only S=0 mesons; = 5520 only S=1 mesons. The vector
      mesons are produced with transverse  or  longitudinal polarisation

      and decayed accordingly.

    - High transverse momentum,  scalar Higgs production, in association
      with a jet, is now available as IPROC =2300. Only the top quark is
      included in the loops with IAPHIG controlling the approx. used: =0
      zero top mass limit; = 1 exact result; = 2 infinite top mass limit
      (default 1). Note the routines: HWHGJ1, HWHGJA, HWHGJB/C/D, HWUCI2
      and HWULI2 use (non-standard FORTRAN-77)  DOUBLE COMPLEX variables
      which may not be accepted by some compilers.   Users can change to
      COMPLEX variables, however this involves a risk of rounding errors
      spoiling numerical cancellations.

    - DIS with neutrino beams is now available in processes IPROC= 90**.

  * The DIS O(alpha_s) jet production processes, IPROC = 92**, have been
    withdrawn and are no longer supported.

  * A running electromagnetic coupling has been introduced,  HWUAEM(Q2).
    ALPHEM (now a single variable)  sets the Thomson limit (Q2=0) value,
    default = 0.0072993 (1/137.0).

  * Two new particles have been created: 'REMG', IDHW=71, IDHEP=9998 and
    'REMN',  IDHW=72,  IDHEP=9999   are  remnant  photons  and  nucleons
    respectively.  They are identical to photons & nucleons, except that
    gluons are labelled as valence partons and, for the nucleon, valence
    quark distributions are set to zero. They are used internally by the
    JIMMY generator for multiple interactions,  and are not intended for
    general use.

  * An error in setting the scale EMCMF (now called EMSCA) for QCD
    decays of colour neutral particles, preventing parton showers, has
    been corrected.

  * Minor bugs have been corrected in:  phi decays to neutral kaons; the
    weights for photo-production processes; the value of EVWGT in di-jet
    production by point-like photons.

  * The transverse momentum cutoff  for final-state photon emission from
    quarks, VPCUT, now defaults to 0.4 GeV.  Previous versions defaulted
    to SQRT(S), switching off such emission.

  * The default top quark mass has been increased to 170 GeV/c^2

    Version 5.1 of  HERWIG was described  in detail in  Computer Physics
    Communications 67 (1992) 465. For completeness we list here also the
    main new features added in versions 5.2 - 5.7.

    In version 5.2:

  * New e+e- processes:
    - two photon processes, IPROC = 500+ID  where ID=0-10 is the same as
      in Higgs processes for qqbar, llbar, and W+W-.  The phase space is
      controlled  by  EMMIN,EMMAX for the CMF mass,  PTMIN,PTMAX for the
      transverse momentum of the CMF in the lab,  and CTMAX  for the CMF
      angle of the outgoing particles.
    - photon-W fusion,  IPROC = 550+ID  where  ID=0-9 is the  same as in
      Higgs processes,  except that ID=1 or 2 both give the sum of dubar
      and udbar etc.  The phase space is controlled by EMMIN,EMMAX only.
      The full 2-->3 matrix elements for photon e-->f f'bar nu are used,
      so the cross-section  for real W production is correctly included.
    - ZZ pair production,  IPROC=250 is treated just like WW production,
      and is based on the program kindly supplied by Zoltan Kunszt.

  * New ep processes:
    - the phase space for BGF is now controlled by EMMIN,EMMAX as above.
      The default values are 0 and RootS respectively,  corresponding to
      the behaviour of version 5.1
    - J/psi production from BGF, IPROC = 9104 is now available.
    - W W fusion to Higgs is now available in ep, IPROC = 9500+ID.

  * IPROC = 1600+ID now gives the sum of gluon fusion and q qbar fusion.
    This is especially important in e+e- if tan(beta) is large,  when it
    is dominated by e+e- --> e+e- gamma gamma --> e+e- b bbar H.

  * Users can now force  Z --> b bbar  decays,  with MODBOS(i)=7  (for a
    complete list see Sect. 15).  For example,  IPROC=250,  MODBOS(1)=7,
    MODBOS(2)=0 gives ZZ production with one Z decaying to b bbar.

  * All Higgs vertices now include an enhancement factor to  account for
    non-SM couplings. ENHANC(ID), where ID=1-11 is the same as for Higgs
    production, holds the ratio of the AMPLITUDE for the given vertex to
    that of the SM. This of course only simulates the chargeless scalars
    of any extended model, and not the pseudoscalars or charged Higgses.

  * The heavy quark  content of the photon  now uses the  corrections to
    the Drees-Grassie distribution functions for light quarks,  recently
    calculated by C.S.Kim et al. (see M.Drees & C.S.Kim, DESY 91-039 and
    C.S.Kim, Durham preprint DTP/91/16).

  * A new structure function set, Owens1.1, similar to Duke+Owens1, but
    fitted to new data (Preprint FSU-HEP-910606) is available via
    NSTRU=5, and is now the default structure function set.

    In version 5.3:

  * O(alpha-s) jet production in ep processes has been included (IPROC=
    9200 etc),  with Q**2 range controlled by  Q2MIN, Q2MAX and minimum
    jet transverse momentum  (in the hard subprocess c.m. frame) set by
    PTMIN. The new subroutines were written by Sebastian Brandis and we
    are grateful to him for permission to use his code.

  * Minor bugs have been fixed in the  backward evolution of quarks into
    photons,  hadronic  processes  in e+e-, remnant hadronization in ep,
    and in the  generation of weighted events  (ie. with NOWGT=.FALSE.).

    In version 5.4:

  * A correction to  hard gluon  emission in e+e- events  has been added
    and is now the  default  process.  This uses the  O(alpha-s)  matrix
    element to add events in the  `back-to-back'  region of  phase-space
    corresponding to a quark-antiquark pair  recoiling from a  very hard
    gluon.  Although this is asymptotically  negligible,  and  cannot be
    produced  within the shower itself,  it has a sizeable effect at LEP
    energies.   As a result,  the default parameters  have been retuned,
    and show a marked improvement in agreement with  OPAL data for event
    shapes sensitive to  three-jet  configurations  (J.W. Gary,  private
    communication).   The  uncorrected  process  has  been  retained for
    comparative purposes and is available as IPROC=120+IQ.

  * Photons are now included in  time-like parton showering.  The infra-
    red cutoff is VPCUT,  which defaults to SQRT(S)  corresponding to no
    emission.  Agreement with LEP data is satisfactory  if used together
    with the  matrix element correction  to produce photons in the back-
    to-back region.  The results are  insensitive  to  VPCUT  variations
    in the range 0.1-1.0 GeV.

  * W decay correlations and width are  now correctly included in  W+jet
    production (previous versions used unpolarized, on-shell approx.).

  * An inconsistency in  the argument used for  alpha_s in the branching
    g -> q qbar has been removed. The change is a non-leading correction
    but leads to slightly more quarks in gluon jets.

  * A new parameter  B1LIM  has been introduced for  B cluster hadroniz-
    ation.  If  MCL is the B cluster mass and  MTH the threshold for its
    decay into 2 hadrons,  the probability of  its decay into a single B
    hadron is:   1 if MCL<MTH,   0 if MCL>(1+B1LIM)*MTH,   with a linear
    interpolation i.e. 1-(MCL-MTH)/(B1LIM*MTH) if MTH<MCL<(1+B1LIM)*MTH.
    Thus the default value  B1LIM=0 gives the same as previous versions,
    while B1LIM>0 gives a harder B spectrum.

  * B decays can now be performed by the  EURODEC  or  CLEO  Monte Carlo
    packages.  The new variable  BDECAY  controls which package is used:
    'HERW' for HERWIG; 'EURO' for EURODEC; 'CLEO' for CLEO.  The EURODEC
    package can be obtained from the CERN library.   The CLEO package is
    available by  kind permission of the CLEO collaboration,  and can be
    obtained from Luca Stanco at the address given above.

    In version 5.5:

  * The Sudakov form factors can now be calculated using the one-loop or
    two-loop alpha_s, according to the variable SUDORD (DEFAULT=1).  The
    parton showering  still incorporates  the two-loop alpha_s in either
    case but if SUDORD=1 this is done using the veto algorithm,  whereas
    if SUDORD=2 no vetoes  are used in the  final-state evolution.  This
    means that the  relative weight of any  shower configuration  can be
    calculated in a closed form, and hence that showers can be `forced'.
    For example,  a package of  routines  should  be available  soon for
    forcing jets to contain  photons,  which will therefore  drastically
    improve the efficiency of photon FSR studies.
    To next-to-leading order  the two possibilities SUDORD=1 or 2 should
    be identical,  but they  differ  at beyond-NLO,  so some results may
    change a little. Previous versions were equivalent to SUDORD=1.

  * Alpha_em is now multiplied by the factor ALPFAC (DEFAULT=1)  for all
    quark-photon vertices in jets, and in the `dead zone' in e+e-.  This
    is a cheap  way of improving  the efficiency of  photon FSR studies,
    which should  not be needed  once photon forcing is available.  Note
    that results at small ycut become sensitive to ALPFAC above about 5.

  * A new parameter CLPOW (DEFAULT=2) is available in the cluster hadro-
    nization model.  A cluster of mass  MCL made of quarks of mass M1,M2
    is split into lighter clusters before decaying if
                 MCL**CLPOW > CLMAX**CLPOW + (M1+M2)**CLPOW
    Thus the previous value was CLPOW=2,  like the new default.  Smaller
    values will  increase the  yield of  heavier clusters  (and hence of
    baryons) for heavy quarks, without affecting light quarks much.  For
    example, the default value gives no b-baryons (for the default value
    of CLMAX) whereas CLPOW=1.0 makes b-baryons/b-hadrons about 1/4.

  * The event record has been modified to retain entries for all partons
    before hadronization  (with status ISTHEP=2).  During hadronization,
    the gluons are split  into quark-antiquark,  while other partons are
    copied to a location  (indicated by JDAHEP(1,*)) where their momenta
    may be shifted slightly, to conserve momentum,  during heavy cluster
    splitting. Previously the original momenta were shifted, so momentum
    appeared not to be conserved at the parton level.

  * Minor improvements have been made to: NLO correction to Higgs decays
    to qqbar;  pt spectra of outgoing electrons in two-photon processes;
    quark-mass effects in gamma-W fusion; WW spectrum below threshold in
    e+e-; t-bbar spectrum in W Drell-Yan (IPROC=1406).

  * Bugs preventing the use of  Sudakov form factor tables from disk and
    gluon-> diquarks splitting option under some circumstances, together
    with other minor bugs and machine-dependences, have been fixed.

    In version 5.6:

  * Decays of very heavy quarks  (top and higher generations)  can occur
    either before or after hadronization. At present all top quarks will
    decay  before/after hadronizing if the top mass is greater/less than
    130 GeV.  This can be changed in subroutine HWDTOP.  All higher (>3)
    generations now decay before hadronization. Note that the new state-
    ment  CALL HWDHQK  must appear in the main program between the calls
    to  HWBGEN and HWCFOR  to carry out any decays before hadronization.

  * Bugs in the subroutine  HWHDOA for O(alpha_s)  jet production in DIS
    have been corrected by J. Chyla,  who has also extended this process
    into the photoproduction region. If Q2MIN.LT.2D-6 (the new default),
    the kinematic lower limit on Q**2 is computed and used.  New options
    IPROC=9250 to 9277 use various approximations to the neutral-current
    matrix element, as specified in the Table below.

  * The photoproduction  processes  have  also  been  extended  from the
    original  heavy quark production program,  to include all quark pair
    production  (IPROC=9100-9106)  and QCD Compton (IPROC=9110-9122), as
    well as the sum of the two  (IPROC=9130).  The possible flavours for
    the 9100,9110 and 9130 processes are limited by the input parameters
    IFLMIN and IFLMAX  (defaults are 1 and 3, i.e. only u,d,s flavours).
    The corresponding Charged Current processes are now provided via the
    IPROC=9140-9144 codes.

  * All the DIS processes  IPROC=9000-9599  are now available in e+e- as
    well as  lepton-hadron  collisions.  The program  generates a photon
    from the second beam (only) in Weizsacker-Williams approximation and
    uses Drees-Grassie structure functions for DIS on the photon.

  * Pointlike photon-hadron scattering  to produce QCD jets is available
    as IPROC=5000.  This is suitable for  fixed-target  photoproduction,
    provided events  are generated in  a frame in  which the  target has
    high momentum, and then boosted back to the lab.  IPROC=5000+IQ gen-
    erates only those processes involving quark flavour IQ,  using exact
    kinematics and  light-cone  momentum fraction.  In both cases, after
    event generation the hard subprocess code  IHPRO is set to  51,52 or
    53 for photon+q->g+q, photon+qbar->g+qbar, or photon+g->q+qbar.

  * The default limits on Q**2 in DIS processes  (Q2MIN,Q2MAX) have been
    set very  small/large  (0.0, 1.D10)  and are reset  to the kinematic
    limits unless  changed by the user.  This means the default Q2MIN is
    not suitable for simple NC DIS (IPROC=9000 etc),  but is appropriate
    for jet and heavy quark photoproduction.

  * A new parameter  NMXJET,  the maximum number of  outgoing partons in
    a hard subprocess  (default 200)  has been  introduced in the common
    block file HERWIG56.INC.

  * For technical reasons, some HERWIG status codes  ISTHEP  between 153
    and 165 have changed their meanings. See the Table in Sect.10 below.

  * Bugs in the hadronization of  diquark-antidiquark clusters have been
    fixed. Any such clusters with  masses below threshold for decay into
    baryon-antibaryon are shifted to the  threshold via a transfer of 4-
    momentum to a neighbouring cluster.

  * A bug in the default pion structure function (no gluons) is fixed.

    In version 5.7:

- ELECTRO-WEAK COUPLINGS: New arrays QFCH(16), VFCH(16,2), AFCH(16,2)
  and VCKM(3,3) have been set up for couplings and CKM matrix.  See the
  documentation file or HWIGIN for conventions.  Note that universality
  is not assumed, so lepton axial couplings may differ for example; this
  is primarily to cover Z' possibilities, see below. The variable
  SCABI=sin^2 theta_Cabibbo is however also retained for the present.

- A Z' has been introduced with PDG code 32, HERWIG identifier 202,
  default mass 500 GeV, width GAMZP (default 5 GeV) and name 'Z0PR'.
  It is invoked by setting ZPRIME=.TRUE. (default .FALSE.).

- POLARISATION: incoming lepton and antilepton beam polarisations
  are now specified by setting two new vectors EPOLN(3) and PPOLN(3):
  component 3 is longitudinal and 1,2 transverse. Transverse only occurs
  in e+e- routines; recall that two transverse 'measurements' are needed
  to see an effect so it should not arise elsewhere. Note that in DIS
  processes you have to set either EPOLN if it is a lepton or (exclusive)
  PPOLN if an antilepton.

  Polarisation effects are now included in e+e- 2/3 jet production
  and Bjorken process, together with DIS processes apart from J/psi
  production.

- NEW SUBPROCESSES:
  2200    QCD direct photon pair production (inc. g+g->gamma+gamma)
  5100+IQ Point-like photon/QCD heavy flavour pair production
  5200+IQ Point-like photon/QCD heavy flavour single excitation
  The latter two replace 5000+IQ, while 5000 remains as before (ie
  a sum over all processes and flavours with simplified kinematics)

- The kinematic reconstruction of DIS processes can now take place in
  the Breit frame, if BREIT=.TRUE. (the default value). Previous versions
  used the lab frame. Although the reconstruction is fully invariant under
  Lorentz boosts along the incoming hadron's direction, it is not under
  transverse boosts, so there should be some difference between the two
  frames. The boost is not performed for very small Q^2 (<10^-4) to avoid
  numerical instabilities, but the two frames are in any case equivalent
  for such small Q^2.

- A new parameter PRSOF to produce an underlying event in only a fraction
  PRSOF of events (default=1.0).  IPROC=19000 etc are thus equivalent to
  PRSOF=0.

- Non-diffractive hadronic minimum bias events (IPROC=8000) can now be
  generated for a wider variety of beams (P,PBAR,PI+/-,K+/-,E+/-,MU+/-,GAMA
  on target P; also P and PBAR or leptons on target N). The event weight
  (previously set to 1.0 for this process) is the estimated cross section
  based on the parametrizations of Donnachie and Landshoff, CERN-TH.6635/92.
  The non-diffractive cross section is assumed to be 70% of the total.
  For lepton beams a photon is first generated using the effective photon
  approximation (see below) and then the on-shell photon cross section
  is used.

- A bug has been fixed in HWBRAN and HWSBRN (present in versions 5.1 to
  5.6) that led to too much transverse momentum being developed by the
  parton showers in hadron-hadron collisions. All radiation with pt
  greater than the hard process scale is now vetoed. In the case of
  initial-state radiation, this affects all events, while for final-state
  radiation it only affects those in which the two jets have a rapidity
  difference of more than about 3.4.

- When SUDORD=2, no veto is needed for gluon splitting to quarks. This
  means that no vetoes are needed for final state showering, except for
  the previously-mentioned transverse momentum cut. The removal of
  vetoes allows preselection of the flavours that a jet will contain,
  giving a huge increase in the efficiency of rare process simulation. A
  package is already available to simulate heavy flavour production
  inside jets, and the equivalent for photons should soon be available.

- Parameter BTCLM is now available to users to adjust the mass parameter
  in remnant formation. Its default value, 1.0, is identical to previous
  versions.

- There is a new switch CLDIR for cluster decays. CLDIR=0 is the same as
  previous versions, while CLDIR=1 (the default) means that a cluster that
  contains a `perturbative' quark, ie one coming from the perturbative
  stage of the event (the hard process or perturbative gluon splitting)
  `remembers' its direction: when the cluster decays, the hadron carrying
  its flavour continues in the same direction (in the cluster c.m. frame)
  as the quark. This considerably hardens the spectrum of heavy hadrons,
  particularly of c- and b-flavoured hadrons. It also introduces a tendency
  for baryon-antibaryon pairs preferentially to align themselves with the
  event axis (the `TPC/2gamma string effect').

- The functionality of the routine HWUINE has now been split between it
  and a new routine, HWUFNE. A call to the latter MUST be inserted into
  the users main program, between the calls to HWMEVT and HWANAL. A
  check is built in to version 5.7 to prevent execution if this change
  is not made. See the documentation file for an example main program.
  We should also take this opportunity to remind users that the analysis
  routine HWANAL should begin with the line
      IF (IERROR.NE.0) RETURN
  since if an event is cancelled, each of the routines is still called
  in turn until reaching the end of the main loop.

- If the new flag USECMF is .TRUE. (the default), events are boosted to
  their centre-of-mass frame before processing if necessary, and boosted
  back afterwards.  This second boost is performed by the new routine
  HWUFNE, so it is essential that this is inserted in the correct place,
  as described above.

- In hadronic processes with lepton beams (eg photoproduction in ep),
  the lepton->lepton+photon vertex now uses the full tranverse-momentum-
  dependent splitting function, with exact light-cone kinematics (i.e.
  the Equivalent Photon instead of the Weizsacker-Williams approximation).
  This means that the photon-hadron collision has a transverse momentum
  in the lepton-hadron frame, and must be boosted to a frame where it
  has no transverse momentum. Thus the cmf boost described above is
  always used in these processes, regardless of the value of USECMF.
  The correct lower energy cut-off appropriate to the hadronic process
  is applied to the photon, rather than the fixed cut of 5 GeV that
  was used in previous versions. The Q**2 of the photon is generated
  within the kinematically allowed limits, or the user-defined limits
  Q2WWMN and Q2WWMX (defaults 0 and 4) whichever is more restrictive.
  The momentum fraction is generated within the kinematic limits or
  between YBMIN and YBMAX (defaults 0 and 1).

- Point-like photon processes (IPROC=5***) are now also available with
  lepton beams, using the Equivalent Photon Approximation.

- Several minor improvements have been made to the O(as) processes in
  DIS (IPROC=91**):
  - A sign error has been corrected that led to the incorrect sign for
    the lepton-jet azimuthal correlation in QCD Compton processes.
  - An additional cut on the phase-space generation has been provided:
    the Bjorken-y variable (=Q^2/xs) is limited to range [YBMIN,YBMAX].
  - BGSHAT=.FALSE. is now the default.
  - J/Psi production (IPROC=9107) now uses the EPA instead of the WWA,
    with the same phase-space cuts as hadronic processes with lepton
    beams, see above.

- Many bugs have been fixed in the other O(as) process routines, HWHDOA
  and HWHDOM, ie for IPROC=92**. However, this process is no longer
  supported, and is only retained for comparative purposes. It will be
  withdrawn completely at the next version release.

- An interface is now provided to Mark Gibbs' HERBVI package for baryon-
  number violation, and other multi-W production processes, IPROC=7***.

- Minor bug fixes in HWHDIS, HWHEGW and HWHIGW and minor improvements in
  HWHHVY, HWHPHO, HWHQCD and HWHWEX hard process routines.

- New fictional e+e- processes: e+e- -> gluon+gluon(+gluon), IPROC=107
  & 127, treated just like e+e- -> quark+antiquark, summed over light
  quark flavours, for direct comparisons between quark and gluon jets.

- New logical variable PRNDEC (default=.TRUE. unless NMXHEP>9999) causes
  track numbers in event listings to be printed in hexadecimal if.FALSE.
  This is necessary for very large events such as those generated by the
  HERBVI package (see above).

- PDFLIB structure functions can now be used for the photon as well as
  nucleons. The new variable MODPHO acts just like MODPDF. PDFLIB calls
  have also been updated to allow for structure function sets with
  flavour-asymmetric sea contributions.

- A logical inconsistency has been fixed in the decays of clusters to
  eta or eta' - previously all mixing was neglected, leading to double-
  counting and a significant over-estimate of the number of each. The
  new variable ETAMIX gives the eta_8/eta_0 mixing angle in degrees
  (default = -20). Rates are not very sensitive to its exact value, as
  the eta'/eta suppression is dominated by mass effects in the cluster
  model.

- The maximum weight is now always printed in full precision (needed
  to be sure of generating the same events in repeated runs).

- New constants:  GEV2NB=389385 
                  ALPHEM(1)=1./137(.03599)    for Q^2=0.
                  ALPHEM(2)=1./128            for Q^2~M_W^2
  are introduced in various cross section formulae, and G_Fermi is
  eliminated.

- The default top quark mass was increased to 150 GeV.

 -----------------------------------------------------------------------

                  *** 3. FEATURES NOT YET INCLUDED***

   Note that the following features are NOT yet included in the program:
   polarization  of  produced  heavy  quarks  and leptons;  treatment of
   coherence  in the  small-x region  of incoming  jets  (see S. Catani,
   F. Fiorani  and  G. Marchesini,  Nucl.Phys. B336(1990)18);   multiple
   parton  interactions  and  parton  shadowing;  diffractive processes;
   QED radiative corrections; W/Z bosons within parton showers.

 -----------------------------------------------------------------------

                     ***** 4. PROGRAM STRUCTURE*****

   The main program HWIGPR has the following form:

      PROGRAM HWIGPR
C---COMMON BLOCKS ARE INCLUDED AS FILE HERWIG58.INC
      INCLUDE 'HERWIG58.INC'
      INTEGER N
C---MAX NUMBER OF EVENTS THIS RUN
      MAXEV=100
C---BEAM PARTICLES
      PART1='PBAR'
      PART2='P   '
C---BEAM MOMENTA
      PBEAM1=900.
      PBEAM2=900.
C---PROCESS
      IPROC=1500
C---INITIALISE OTHER COMMON BLOCKS
      CALL HWIGIN
C---USER CAN RESET PARAMETERS AT
C   THIS POINT, OTHERWISE DEFAULT
C   VALUES IN HWIGIN WILL BE USED.
      PTMIN=1000.
C---COMPUTE PARAMETER-DEPENDENT CONSTANTS
      CALL HWUINC
C---CALL HWUSTA TO MAKE ANY PARTICLE STABLE
      CALL HWUSTA('PI0 ')
C---USER'S INITIAL CALCULATIONS
      CALL HWABEG
C---INITIALISE ELEMENTARY PROCESS
      CALL HWEINI
C---LOOP OVER EVENTS
      DO 100 N=1,MAXEV
C---INITIALISE EVENT
      CALL HWUINE
C---GENERATE HARD SUBPROCESS
      CALL HWEPRO
C---GENERATE PARTON CASCADES
      CALL HWBGEN
C---DO HEAVY QUARK DECAYS
      CALL HWDHQK
C---DO CLUSTER FORMATION
      CALL HWCFOR
C---DO CLUSTER DECAYS
      CALL HWCDEC
C---DO UNSTABLE PARTICLE DECAYS
      CALL HWDHAD
C---DO HEAVY FLAVOUR HADRON DECAYS
      CALL HWDHVY
C---ADD SOFT UNDERLYING EVENT IF NEEDED
      CALL HWMEVT
C---FINISH EVENT
      CALL HWUFNE
C---USER'S EVENT ANALYSIS
      CALL HWANAL
  100 CONTINUE
C---TERMINATE ELEMENTARY PROCESS
      CALL HWEFIN
C---USER'S TERMINAL CALCULATIONS
      CALL HWAEND
      STOP
      END

   Various phases of the  simulation can be  suppressed by  deleting the
   corresponding  subroutine  calls,  or  different  subroutines  may be
   substituted.  For example,  in studies at the parton level everything
   from CALL HWDHQK to CALL HWMEVT can be omitted.

   The following is a full list of subroutines and functions,  which are
   classified  according to their initial letters.  The starred sections
   may be  omitted for  certain  event types  provided the corresponding
   subroutine  calls  are  suppressed  in  HWIGPR or HWBGEN.  Brief sub-
   routine descriptions may be found in Sect. 20.

   Main program and initialisation:

   HWIGPR  HWIGIN

   User-provided routines to initialise, perform and terminate
   user's analysis of event data:

   HWABEG  HWAEND  HWANAL

   Parton branching generation with interfering gluons:

   HWBAZF  HWBCON  HWBDED  HWBDIS  HWBFIN  HWBGEN  HWBJCO  HWBMAS
   HWBRAN  HWBSPA  HWBSPN  HWBSU1  HWBSU2  HWBSUD  HWBSUG  HWBSUL
   HWBTIM  HWBVMC

   Cluster hadronization model:

   HWCCUT  HWCDEC  HWCFLA  HWCFOR  HWCGSP  HWCHAD

   Decay of unstable particles and heavy flavours:

   HWDBOS  HWDBOZ  HWDCLE  HWDEUR  HWDHAD  HWDHGC  HWDHGF  HWDHIG
   HWDHQK  HWDHVY  HWDIDP  HWDPWT  HWDTHR  HWDTOP  HWDTWO  HWDWWT

   Elementary subprocess generation:

   HWEFIN  HWEGAM  HWEINI  HWEONE  HWEPRO  HWETWO

   Individual hard subprocesses:

   HWHBGF  HWHBKI  HWHBRN  HWHBSG  HWHDIS  HWHDYP  HWHEGG  HWHEGW
   HWHEGX  HWHEPA  HWHEPG  HWHEW0  HWHEW1  HWHEW2  HWHEW3  HWHEW4
   HWHEW5  HWHEWW  HWHHVY  HWHIG1  HWHIGA  HWHIGB  HWHIGJ  HWHIGM
   HWHIGS  HWHIGT  HWHIGW  HWHIGY  HWHIGZ  HWHPH2  HWHPHO  HWHPPB
   HWHPPE  HWHPPH  HWHPPM  HWHPPT  HWHQCD  HWHQCP  HWHW1J  HWHWEX
   HWHWPR

  *Soft minimum-bias hadron-hadron collision or underlying event:

   HWMEVT  HWMLPS  HWMNBI  HWMULT  HWMWGT

   Random number generators:

   HWRAZM  HWREXP  HWREXQ  HWREXT  HWRGAU  HWRGEN  HWRINT  HWRLOG
   HWRPOW  HWRUNG  HWRUNI

  *Spacelike branching of incoming partons:

   HWSBRN  HWSDGG  HWSDGQ  HWSFBR  HWSFUN  HWSGAM  HWSGEN  HWSGQQ
   HWSSPC  HWSSUD  HWSTAB  HWSVAL

   Miscellaneous utilities:

   HWUAEM  HWUAER  HWUALF  HWUBPR  HWUBST  HWUCFF  HWUCI2  HWUDAT
   HWUECM  HWUEDT  HWUEEC  HWUEMV  HWUEPR  HWUFNE  HWUGAU  HWUIDT
   HWUINC  HWUINE  HWULDO  HWULI2  HWULOB  HWULOF  HWULOR  HWUMAS
   HWUPCM  HWURAP  HWURES  HWUROB  HWUROF  HWUROT  HWUSOR  HWUSQR
   HWUSTA  HWUTAB  HWUTIM

   Vector manipulation:

   HWVDIF  HWVDOT  HWVEQU  HWVSCA  HWVSUM  HWVZRO

   Warning messages and error handling:

   HWWARN

   Dummy versions of the external routines

   PDFSET  STRUCTM
   EUDINI  FRAGMT  IEUPDG  IPDGEU
   DECADD  QQINIT  QQLMAT  IUCOMP
   HVCBVI  HVHBVI

   should be deleted if the structure function library,  EURODEC B decay
   package,  CLEO B decay package,  or HERBVI (respectively) is linked.
 -----------------------------------------------------------------------

                     *** 5. BEAMS AND PROCESSES***

   As indicated above, a number of variables must be set in the main
   program to specify what is to be simulated:

         +----------+----------------------------------+-------+
         |   Name   |     Description                  |Default|
         +----------+----------------------------------+-------+
         | PART1    | Type of particle in beam 1       | 'PBAR'|
         | PART2    | Type of particle in beam 2       | 'P   '|
         | PBEAM1   | Momentum of beam 1               | 900.  |
         | PBEAM2   | Momentum of beam 2               | 900.  |
         | IPROC    | Type of process to generate      | 1500  |
         | MAXEV    | Number of events to generate     | 100   |
         +----------+----------------------------------+-------+

    The beam particle types PART1,PART2 supported at present are:

              +-------------------------------------------+
              | 'E+  ','E-  ','MU+ ','MU- ','NUE ','NUEB' |
              | 'NUMU','NMUB','NTAU','NTAB','GAMA',       |
              | 'P   ','PBAR','N   ','NBAR','PI+ ','PI- ' |
              +-------------------------------------------+

    In addition, beams 'K+  ' and 'K-  ' are supported for minimum
    bias non-diffractive soft hadronic events (IPROC=8000) only.

    The currently available processes IPROC are tabulated below.

  +---------+--------------------------------------------------------+
  |  IPROC  |                     Process                            |
  +---------+--------------------------------------------------------+
  | 100     | e+ e-  -> q qbar (gluon) (all flavours)                |
  | 100+IQ  | e+ e-  -> q qbar (gluon) (IQ=1--6 for q=d,u,s,c,b,t)   |
  | 107     | e+ e-  -> gluon gluon (gluon) fictitious process       |
  | 110     | e+ e-  -> q qbar gluon (all flavours)                  |
  | 110+IQ  | e+ e-  -> q qbar gluon (IQ as above)                   |
  | 120     | e+ e-  -> q qbar (all flavours)| without correction to |
  | 120+IQ  | e+ e-  -> q qbar (IQ as above) | hard gluon branching  |
  | 127     | e+ e-  -> gluon gluon          |                       |
  | 150+IL  | e+ e-  -> l lbar (IL=2,3 for l=mu,tau)                 |
  +---------+--------------------------------------------------------+
  | 200     | e+ e-  -> W+ W- (see Sect. 15 on control of W/Z decays)|
  | 250     | e+ e-  -> Z0 Z0 (see Sect. 15 on control of W/Z decays)|
  +---------+--------------------------------------------------------+
  | 300     | e+ e-  -> Z H -> Z q qbar (all flavours)               |
  | 300+IQ  | e+ e-  -> Z H -> Z q qbar (IQ as above)                |
  | 306+IL  | e+ e-  -> Z H -> Z l lbar (IL=1,2,3 for l=e,mu,tau)    |
  | 310,11  | e+ e-  -> Z H -> Z W W, Z Z Z                          |
  | 312     | e+ e-  -> Z H -> Z gamma gamma                         |
  | 399     | e+ e-  -> Z H -> Z anything                            |
  +---------+--------------------------------------------------------+
  | 400+ID  | e+ e-  -> nu nu H + e e H (ID as in IPROC=300+ID)      |
  +---------+--------------------------------------------------------+
  | 500+ID  | e+ e-  -> gamma gamma -> qqbar/llbar/WW (ID=0-10 as in |
  |         |                                          IPROC=300+ID) |
  | 550+ID  | e+ e-  -> gamma W -> qq'bar/ll'bar      (ID=0-9)       |
  +---------+--------------------------------------------------------+
  | 1350    | q qbar -> Z0/gamma -> l lbar (all lepton species)      |
  | 1350+IL | q qbar -> Z0/gamma -> l lbar (IL as above)             |
  +---------+--------------------------------------------------------+
  | 1400    | q qbar -> W+/- -> q' qbar'' (all flavours)             |
  | 1400+IQ | q qbar -> W+/- -> q' qbar'' (q' or q'' as above)       |
  | 1450    | q qbar -> W+/- -> l nul (all lepton species)           |
  | 1450+IL | q qbar -> W+/- -> l nul (IL as above)                  |
  | 1499    | q qbar -> W+/- -> anything                             |
  +---------+--------------------------------------------------------+
  | 1500    | QCD  2 -> 2 hard parton scattering                     |
  |         | After generation, IHPRO is subprocess (see list)       |
  +---------+--------------------------------------------------------+
  | 1600+ID | q qbar/g g -> Higgs (ID as in IPROC=300+ID)            |
  +---------+--------------------------------------------------------+
  | 1700+IQ | QCD heavy quark production (IQ as above)               |
  |         | After generation, IHPRO is subprocess (see list)       |
  +---------+--------------------------------------------------------+
  | 1800    | QCD direct photon + jet production                     |
  |         | After generation, IHPRO is subprocess (see list)       |
  +---------+--------------------------------------------------------+
  | 1900+ID | q qbar -> q' qbar' H (ID as in IPROC=300+ID)           |
  +---------+--------------------------------------------------------+
  | 2000    |    t production via W exchange (sum of 2001-2008)      |
  | 2001,2  |    ubar bbar -> dbar tbar,   d bbar -> u tbar          |
  | 2003,4  |    dbar bbar -> ubar tbar,   u b    -> d t             |
  | 2005,6  |    cbar bbar -> sbar tbar,   s bbar -> c tbar          |
  | 2007,8  |    sbar b    -> cbar t   ,   c b    -> s t             |
  +---------+--------------------------------------------------------+
  | 2100    | W + jet production.                                    |
  | 2110,20 | Compton only (g q -> W q), annih. only (q qbar -> W q) |
  +---------+--------------------------------------------------------+
  | 2200    | QCD direct photon pair production (see list for IHPRO) |
  +---------+--------------------------------------------------------+
  | 2300    | QCD Higgs plus jet production (see list for IHPRO)     |
  +---------+--------------------------------------------------------+
  | 5000    | Pointlike photon-hadron jet production (all flavours)  |
  | 5100+IQ | Pointlike photon heavy flavour IQ pair production      |
  | 5200+IQ | Pointlike photon heavy flavour IQ single excitation    |
  |         | After generation, IHPRO is subprocess (see list)       |
  | 5500    | Pointlike photon production of light (u,d,s) L=0 mesons|
  | 5510,20 | S=0 mesons only, S=1 mesons only (see list for IHPRO)  |
  +---------+--------------------------------------------------------+
  | 7000 -  | Baryon-number violating and other multi-W processes    |
  | 7999    | generated by HERBVI package                            |
  +---------+--------------------------------------------------------+
  | 8000    | Minimum bias non-diffractive soft hadron-hadron event  |
  +---------+--------------------------------------------------------+
  | 9000    | Deep inelastic lepton scattering (all neutral current) |
  | 9000+IQ | Deep inelastic lepton scattering (NC on flavour IQ)    |
  | 9010    | Deep inelastic lepton scattering (all charged current) |
  | 9010+IQ | Deep inelastic lepton scattering (CC on flavour IQ)    |
  +---------+--------------------------------------------------------+
  | 9100+IQ | Boson-gluon fusion in NC DIS, IQ=0-6 as above          |
  | 9107    | J/Psi + gluon production by boson-gluon fusion         |
  | 9110    | QCD Compton process in NC DIS, all flavours            |
  | 9110+IP | QCD Compton process in NC DIS, IP=1-12, d-t, dbar-tbar |
  | 9140+IP | CC proc, IP:1 = s cbar,2 = b cbar,3 = s tbar,4 = b tbar|
  +---------+--------------------------------------------------------+
  | 92**    | Withdrawn: use 91** instead                            |
  +---------+--------------------------------------------------------+
  | 9500+ID | W W fusion -> Higgs in e p (ID as in IPROC=300+ID)     |
  +---------+--------------------------------------------------------+
  |10000+IP | as IPROC=IP but with soft underlying event (hadron     |
  |         | remnant fragmentation in lepton-hadron) suppressed     |
  +---------+--------------------------------------------------------+

 -----------------------------------------------------------------------

                     ***** 6. INPUT PARAMETERS*****

   The quantities that may be regarded as adjustable parameters are

         +----------+----------------------------------+-------+
         |   Name   |     Description                  |Default|
         +----------+----------------------------------+-------+
         | QCDLAM   | QCD Lambda (see below)           | 0.18  |
         +----------+----------------------------------+-------+
         | RMASS(1) | Down    quark mass               | 0.32  |
         | RMASS(2) | Up      quark mass               | 0.32  |
         | RMASS(3) | Strange quark mass               | 0.50  |
         | RMASS(4) | Charmed quark mass               | 1.80  |
         | RMASS(5) | Bottom  quark mass               | 5.20  |
         | RMASS(6) | Top     quark mass               | 100.  |
         +----------+----------------------------------+-------+
         | RMASS(13)| Gluon effective mass             | 0.75  |
         +----------+----------------------------------+-------+
         | VQCUT    | Quark virtuality cutoff (added to| 0.48  |
         |          | quark masses in parton showers)  |       |
         | VGCUT    | Gluon virtuality cutoff (added to| 0.10  |
         |          | effective mass in parton showers)|       |
         | VPCUT    | Photon virtuality cutoff         | 0.40  |
         +----------+----------------------------------+-------+
         | CLMAX    | Maximum cluster mass parameter   | 3.35  |
         | CLPOW    | Power in maximum cluster mass    | 2.00  |
         | PSPLT    | Split cluster spectrum parameter | 1.00  |
         +----------+----------------------------------+-------+
         | QDIQK    | Maximum scale for gluon->diquarks| 0.00  |
         | PDIQK    | Gluon->diquarks rate parameter   | 5.00  |
         +----------+----------------------------------+-------+
         | QSPAC    | Cutoff for spacelike evolution   | 2.50  |
         | PTRMS    | Intrinsic pt in incoming hadrons | 0.00  |
         +----------+----------------------------------+-------+

   Notes on parameters:

  *  QCDLAM can be identified  at high momentum fractions  (x or z) with
     the fundamental QCD scale Lambda-MSbar (5 flavours).  However, this
     relation does not necessarily hold in other regions of phase space,
     since higher order corrections are not treated  precisely enough to
     remove renormalization scheme ambiguities. See S. Catani, G. March-
     esini and B.R.Webber, Nucl. Phys. B349 (1991) 635.

  *  RMASS(1,2,3,13)  are effective light quark and gluon masses used in
     the  hadronization phase  of the program.  They can be  set to zero
     provided the parton shower cutoffs VQCUT and VGCUT are large enough
     to prevent divergences (see below).

  *  For cluster hadronization, it must be possible to split gluons into
     q-qbar, i.e. RMASS(13)  must be at  least twice the  lightest quark
     mass.  Similarly it may be  impossible for heavy flavoured clusters
     to decay if RMASS(4,5) are too low.

  *  VQCUT and VGCUT are needed if the  quark and gluon effective masses
     become small. The condition to avoid divergences in  parton showers
     is
         1/Q(i) + 1/Q(j) < 1/QCDL3  for either i or j or both gluons,
     where  Q(i)=RMASS(i)+VQCUT for quarks,  RMASS(13)+VGCUT for gluons,
     and QCDL3 is the equivalent 3-flavour Lambda computed from  QCDLAM.
     In the notation of  the above reference by  S. Catani et al., QCDL3
     is the 3-flavour equivalent of QCDL5 where
           QCDL5 = QCDLAM*exp(K/(4*pi*beta))/sqrt(2)=1.109*QCDLAM

  *  VPCUT is the analogous quantity for photon emission. It defaults to
     SQRT(S)  corresponding to no emission.  Results after  experimental
     cuts are insensitive to its exact value in the range 0.1 to 1.0 GeV

  *  CLMAX and CLPOW  determine the  maximum allowed  mass of  a cluster
     made from quarks i and j as follows
           Mass**CLPOW < CLMAX**CLPOW + (RMASS(i)+RMASS(j))**CLPOW
     Since the cluster mass spectrum falls rapidly at high mass, results
     become  insensitive to  CLMAX and CLPOW  at large  values of CLMAX.
     Smaller values OF CLPOW will increase the yield of heavier clusters
     (and hence of baryons)  for heavy quarks,  without affecting  light
     quarks  much.  For example,  the default  value gives  no b-baryons
     whereas CLPOW=1.0 makes b-baryons/b-hadrons about 1/4.

  *  PSPLT  determines the  mass  distribution in the  cluster splitting
     CL1 -> CL2 + CL3  when CL1 is above  the maximum allowed mass.  The
     masses of CL2 and CL3 are generated uniformly in Mass**PSPLT. Since
     the number of split clusters is small, dependence on PSPLT is weak.

  *  QDIQK greater than twice the  lightest diquark mass  enables gluons
     to split  non-perturbatively into  diquarks as well as quarks.  The
     probability  of this is  PDIQK*dQ/Q  for scales Q  below QDIQK. The
     diquark masses are taken to be the sum of constituent quark masses.
     Thus the default value QDIQK=0 suppresses gluon->diquark splitting.

  *  QSPAC is the scale below which the structure functions of incoming
     hadrons are frozen and non-valence constituent partons are forced
     to evolve to valence partons, if ISPAC=0.  For ISPAC=2, structure
     functions are frozen at scale QSPAC, but evolution continues down
     to the infrared cutoff.

  *  PTRMS is the width of the (Gaussian) intrinsic  transverse momentum
     distribution of valence partons in incoming hadrons at scale QSPAC.
     (N.B. Neither  QSPAC nor PTRMS  affect  lepton-lepton  collisions.)

   In practice, the parameters  that have been  found most  effective in
   fitting data are QCDLAM,  the gluon effective mass RMASS(13), and the
   cluster mass parameter CLMAX.

   The default parameter values  have been found to give  good agreement
   with event shape  distributions at LEP (OPAL preprint CERN-EP/90-48).

   A number of  further parameters are needed to control the program and
   to turn various options on or off:

         +----------+----------------------------------+-------+
         |   Name   |     Description                  |Default|
         +----------+----------------------------------+-------+
         | IPRINT   | Printout option                  | 1     |
         | MAXPR    | Number of events to print out    | 1     |
         | MAXER    | Max number of errors             | 10    |
         | LWEVT    | Unit for writing output events   | 0     |
         | LRSUD    | Unit for reading Sudakov table   | 0     |
         | LWSUD    | Unit for writing Sudakov table   | 77    |
         | SUDORD   | Alpha_s order in Sudakov table   | 1     |
         +----------+----------------------------------+-------+
         | NRN(1)   | Random number seed 1             | 17673 |
         | NRN(2)   | Random number seed 2             | 63565 |
         | WGTMAX   | Max weight (0 to search for it)  | 0.    |
         | NOWGT    | Generate unweighted events       | .TRUE.|
         +----------+----------------------------------+-------+
         | AZSOFT   | Soft gluon azimuthal correlations| .TRUE.|
         | AZSPIN   | Gluon spin azimuthal correlations| .TRUE.|
         +----------+----------------------------------+-------+
         | NCOLO    | Number of colours                | 3     |
         | NFLAV    | Number of (producible) flavours  | 6     |
         +----------+----------------------------------+-------+
         | MODPDF(I)| PDFLIB structure function set and| -1    |
         | AUTPDF(I)| author group for beam I(=1,2)    | 'MRS' |
         |          | (if MODPDF()<0 do not use PDFLIB)|       |
         | NSTRU    | Input structure function set     | 5     |
         |          | (1,2=Duke-Owens1,2   3,4=EHLQ1,2 |       |
         |          |    5=Owens1.1)                   |       |
         +----------+----------------------------------+-------+
         | ETAMIX   | eta/eta' mixing angle in degrees | -20   |
         +----------+----------------------------------+-------+
         | B1LIM    | B cluster -> 1 hadron parameter  |  0.0  |
         +----------+----------------------------------+-------+
         | CLDIR    | Decay of perturbative clusters,  | 1     |
         |          | 0=>isotropic, 1=>along quark dirn|       |
         | CLSMR    | Width of Gaussian angle smearing | 0.0   |
         +----------+----------------------------------+-------+
         | HARDME   | Use hard and soft matrix-element | .TRUE.|
         | SOFTME   | corrections to e+e- and DIS      | .TRUE.|
         +----------+----------------------------------+-------+
         | BDECAY   | Controls which B Decay package is| 'HERW'|
         |          | used. The allowed values are:    |       |
         |          | 'HERW'; 'EURO'; or 'CLEO'.       |       |
         +----------+----------------------------------+-------+
         | EPOLN(3) | Electron and positron beam       | 0.0   |
         |          | polarizations in DIS and e+e-    | 0.0   |
         |          | annihilation. First two cmpts are| 0.0   |
         | PPOLN(3) | transverse and only used in e+e-,| 0.0   |
         |          | 3rd cmpt is longitudinal, and is | 0.0   |
         |          | +/-1 for fully rh/lh polarized   | 0.0   |
         +----------+----------------------------------+-------+
         | BGSHAT   | Scale=shat for boson-gluon fusion|.FALSE.|
         +----------+----------------------------------+-------+
         | BREIT    | Use Breit frame for DIS kinematix| .TRUE.|
         +----------+----------------------------------+-------+
         | USECMF   | Use hadron-hadron cmf            | .TRUE.|
         +----------+----------------------------------+-------+
         | NOSPAC   | Switch off space-like showers    |.FALSE.|
         +----------+----------------------------------+-------+
         | ISPAC    | Changes meaning of QSPAC,        | 0     |
         |          | see the earlier notes on QSPAC   |       |
         +----------+----------------------------------+-------+
         | PTMIN    | Min pt in hadronic jet production| 10.   |
         | PTMAX    | Max pt in hadronic jet production| 1.E8  |
         | PTPOW    | 1/pt**PTPOW for jet sampling     | 4.    |
         | YJMIN    | Min jet rapidity                 |-8.    |
         | YJMAX    | Max jet rapidity                 | 8.    |
         +----------+----------------------------------+-------+
         | EMMIN    | Min dilepton mass in Drell-Yan   | 10.   |
         | EMMAX    | Max dilepton mass in Drell-Yan   | 1.E8  |
         | EMPOW    | 1/m**EMPOW for Drell-Yan sampling| 4.    |
         +----------+----------------------------------+-------+
         | Q2MIN    | Min Q**2 in deep inelastic       | 0.0   |
         | Q2MAX    | Max Q**2 in deep inelastic       | 1.E10 |
         | Q2POW    | (1/Q**2)**Q2POW for sampling     | 2.5   |
         +----------+----------------------------------+-------+
         | Q2WWMN   | Min Q**2 in Equiv Photon Approx  | 0.0   |
         | Q2WWMX   | Max Q**2 in Equiv Photon Approx  | 4.0   |
         +----------+----------------------------------+-------+
         | PHOMAS   | Damp structure functions for off-| 0.0   |
         |          | shell photons (0 for no damping) |       |
         +----------+----------------------------------+-------+
         | YBMIN    | Min and Max Bjorken-y in DIS and | 0.0   |
         | YBMAX    | Equivalent Photon Approx         | 1.0   |
         +----------+----------------------------------+-------+
         | ZJMAX    | Max Z in J/psi production        | 0.9   |
         +----------+----------------------------------+-------+
         | THMAX    | Max thrust in 3 parton production| 0.9   |
         |          | (equal to 1-Y_cut in JADE scheme)|       |
         +----------+----------------------------------+-------+

     Printout options are:

           IPRINT = 0   Print program title only
                    1   Print selected input parameters
                    2   1 + table of particle codes and properties
                    3   2 + tables of Sudakov form factors

     See Sect. 8 on form factors for details of LRSUD, LWSUD and SUDORD.

     If BGSHAT is false, the scale used for heavy quark production via
     boson-gluon fusion in lepton-hadron collisions will be
             2*shat*that*uhat/(shat**2+that**2+uhat**2)

     If BREIT is true,  the kinematic reconstruction of  deep inelastic
     events  takes place  in the Breit frame  (ie. the frame  where the
     exchanged  boson  is  purely  space-like,  and collinear  with the
     incoming  hadron).    In  fact  the  reconstruction  procedure  is
     invariant  under  longitudinal  boosts,  so any frame in which the
     boson and hadron are collinear would be equivalent, and it is only
     the transverse part of the boost that has an effect.
     The BREIT frame option becomes very inaccurate for very small Q^2.
     It is therefore only used if Q**2 > 1E-4 (the lab and Breit frames
     are anyway equivalent for such small Q**2).
     If BREIT is false, reconstruction takes place in the lab frame.

     If USECMF is true, the entire event record is boost to the hadron-
     hadron cmf before  event processing,  and boosted back afterwards.
     This means that  fixed-target simulation  can be done  in the  lab
     frame, ie with PBEAM2=0.
     For hadronic processes with lepton beams,  this boosting is always
     done, regardless of the value of USECMF.

     The  interface  to  the  PDFLIB  structure  function  package  is
     compatible with PDFLIB versions 3 and 4.  For version 4, AUTPDF()
     should be set to the author group as listed in the PDFLIB manual,
     eg  'MRS',  and MODPDF() to the set number in the new convention.
     For version 3,  AUTPDF() should be set to 'MODE', and MODPDF() to
     the set number in the old convention.

     The `hard' matrix-element correction adds e+e- and DIS events in
     regions of phase-space that cannot be filled by the usual parton
     shower.  The  `soft'  matrix-element  correction moves emissions
     around within the shower  phase-space,   essentially by matching
     the HARDEST emission (which is not necessarily the first) to the
     first-order matrix-element.

     The quantities  from  PTMIN  onwards  control the region of  phase
     space in  which events  are generated and  the importance sampling
     inside those regions.  See Section 11 on event weights for further
     details on  these  quantities  and the use of  WGTMAX  and  NOWGT.

     If hadronic processes with lepton beams are requested,  the photon
     emission vertex  includes the  full  transverse-momentum-dependent
     kinematics  (the Equivalent Photon Approximation).   The variables
     Q2WWMN  and  Q2WWMX  set  the  minimum  and  maximum  virtualities
     generated respectively. For normal simulation, Q2WWMN should be 0,
     and Q2WWMX should be the largest Q**2 through which the lepton can
     be scattered  without  being  detected.  The  variables  YBMIN and
     YBMAX control the range of lightcone momentum fraction generated.

     In addition  there are  options to  give  different weights to the
     various  flavours  of quarks and  diquarks,  and to  resonances of
     different spins.  So far,  these options  have not  been used. See
     the comments in the  initialization  routine  HWIGIN  for details.
 ----------------------------------------------------------------------

                    **** 7. COMMON BLOCK FILE ****

C          ****COMMON BLOCK FILE FOR HERWIG VERSION 5.8****
C ALTERATIONS:DOUBLED NQEV
C             DOUBLED NMXHEP
C             CONVERTED TO DOUBLE PRECISION
C             INTRODUCED NMXSUD (MAX NUMBER OF ENTRIES IN LOOKUP
C               TABLES OF SUDAKOV FORM FACTORS)
C             ADDED NEW VARIABLE RHOHEP: LIKE RHOPAR BUT WITH 3 CMPTS
C  25/7/90    CHANGED TREATMENT OF ALPHA-S
C  3/11/90    CHANGED ORDER (DOUBLE PRECISION FIRST), ADDED EPOLN
C  29/3/91    ADDED NEW COMMON /HWBOSC/, MADE NRN,IBRN ARRAYS(2)
C   1/7/91    ADDED ENHANC(12) TO /HWBOSC/
C 11/11/91    ADDED NEW VARIABLES MODMAX,VPCUT
C  29/1/92    ADDED NEW VARIABLES BDECAY,B1LIM
C  13/3/92    ADDED NEW VARIABLE  CLPOW
C  17/7/92    ADDED NEW VARIABLES ALPFAC,SUDORD
C  9/12/92    ADDED PARAMETER NMXJET (MAX NUMBER OF OUTGOING
C             PARTONS FROM HARD SUBPROCESS)
C  20/1/93    ADDED NEW VARIABLES IFLMIN,IFLMAX
C 18/10/93    ADDED NEW VARIABLES CLDIR,Q2WWMN,Q2WWMX,MODPHO,HVFCEN,
C               PRNDEC,NUMER,NUMERU,FSTEVT,FSTWGT,ETAMIX,BREIT,USECMF
C               TPOL,COSS,SINS,ZPRIME,GAMZP,GEV2NB,QFCH(16),VFCH(16,2),
C               AFCH(16,2),ALPHEM(2),PRSOF,GENSOF,EBEAM1,EBEAM2,IPART1,
C               IPART2,ZJMAX,YBMIN,YBMAX
C             Replaced EPOLN by EPOLN(3) and PPOLN(3)
C                      REQ, AEQ, REQT and IDEQ
C                   by CLQ(6,7), TQWT and MAPQ(6)
C   4/8/94    Added new variables HARDST,HARDME,SOFTME,ISPAC,NOSPAC
C             Changed variable name EMCMF to EMSCA
C             Added new variable CLSMR
C             Added parameter FOUR, new variable IAPHIG
C             Replaced ALPHEM(2) by ALPHEM
C             Replaced MODPDF and MODPHO by MODPDF(2)
C             Put local variable JNHAD into same common as INHAD
C             Added new variable PHOMAS
      IMPLICIT NONE
      DOUBLE PRECISION
     & ZERO, ONE, TWO, THREE, FOUR, HALF
      PARAMETER (ZERO= 0.D0, ONE =1.D0, TWO= 2.D0,
     &           THREE=3.D0, FOUR=4.D0, HALF=0.5D0)
C
      DOUBLE PRECISION
     & PHEP,VHEP,PBEAM1,PBEAM2,QCDLAM,VGCUT,VQCUT,VPCUT,BETAF,CAFAC,
     & CFFAC,CLMAX,CLPOW,PSPLT,QSPAC,PTRMS,PXRMS,QG,QV,SWEIN,SCABI,
     & PDIQK,QDIQK,ENSOF,TMTOP,ZBINM,GAMW,GAMZ,GAMH,PGSMX,PGSPL,PPAR,
     & VPAR,PHIPAR,DECPAR,RHOPAR,RHOHEP,XFACT,PTINT,EVWGT,AVWGT,WGTMAX,
     & WGTSUM,WSQSUM,WBIGST,TLOUT,YJMIN,YJMAX,PTMIN,PTMAX,PTPOW,EMMIN,
     & EMMAX,EMPOW,Q2MIN,Q2MAX,Q2POW,THMAX,QLIM,XXMIN,XLMIN,EMSCA,
     & EMLST,COSTH,GPOLN,GCOEF,XX,DISF,RESN,RMIN,CTMAX,FBTM,
     & FTOP,FHVY,RMASS,BFRAC,CMMOM,ACCUR,QEV,SUD,VECWT,TENWT,DECWT,
     & QWT,PWT,SWT,SWTEF,RESWT,PIFAC,QCDL3,QCDL5,BRHIG,GAMMAX,
     & ENHANC,B1LIM,ALPFAC,Q2WWMN,Q2WWMX,BTCLM,ETAMIX,
     & QFCH,VFCH,AFCH,VCKM,TQWT,CLQ,EPOLN,PPOLN,COSS,SINS,GAMZP,GEV2NB,
     & ALPHEM,PRSOF,EBEAM1,EBEAM2,ZJMAX,YBMIN,YBMAX,HARDST,CLSMR,PHOMAS
C
      INTEGER NMXHEP,NEVHEP,NHEP,ISTHEP,IDHEP,JMOHEP,JDAHEP,
     & IPROC,MAXEV,IPRINT,LRSUD,LWSUD,NCOLO,NFLAV,MODPDF(2),NSTRU,
     & NZBIN,NBTRY,NCTRY,NDTRY,NETRY,NSTRY,NGSPL,NMXPAR,NEVPAR,
     & NPAR,ISTPAR,IDPAR,JMOPAR,JDAPAR,JCOPAR,INHAD,JNHAD,NSPAC,NRN,
     & MAXER,MAXPR,LWEVT,ISTAT,IERROR,NWGTS,IDHW,IBSH,IBRN,IPRO,
     & IFLMIN,IFLMAX,MAXFL,IDCMF,IHPRO,IDN,ICO,LOCN,
     & NRES,IDPDG,ICHRG,MADDR,MODES,MODEF,IDPRO,INTER,NQEV,
     & NSUD,NMXSUD,MODBOS,IOPHIG,MODMAX,SUDORD,CLDIR,NUMER,NUMERU,
     & MAPQ,IPART1,IPART2,ISPAC,IAPHIG
C
      LOGICAL AZSOFT,AZSPIN,FROST,GENEV,BGSHAT,NOWGT,TMPAR,PRNDEC,
     & HVFCEN,FSTEVT,FSTWGT,BREIT,USECMF,ZPRIME,TPOL,GENSOF,
     & HARDME,SOFTME,NOSPAC
C
      CHARACTER*4 PART1,PART2,RNAME,BDECAY
      CHARACTER*20 AUTPDF(2)
C
C---NEW STANDARD EVENT COMMON
      PARAMETER (NMXHEP=2000)
      COMMON/HEPEVT/NEVHEP,NHEP,ISTHEP(NMXHEP),IDHEP(NMXHEP),
     & JMOHEP(2,NMXHEP),JDAHEP(2,NMXHEP),PHEP(5,NMXHEP),VHEP(4,NMXHEP)
C
C---BEAMS, PROCESS AND NUMBER OF EVENTS
      COMMON/HWBEAM/PART1,PART2,IPART1,IPART2
      COMMON/HWPROC/PBEAM1,PBEAM2,EBEAM1,EBEAM2,IPROC,MAXEV
C
C---PARAMETERS (AND QUANTITIES DERIVED FROM THEM)
      COMMON/HWPRAM/QCDLAM,VGCUT,VQCUT,VPCUT,PIFAC,BETAF,CAFAC,CFFAC,
     & CLMAX,CLPOW,PSPLT,QSPAC,PTRMS,PXRMS,QG,QV,SWEIN,SCABI,PDIQK,
     & QDIQK,BTCLM,ENSOF,TMTOP,ZBINM,GAMW,GAMZ,GAMH,QCDL3,QCDL5,B1LIM,
     & PGSMX,PGSPL(4),QFCH(16),VFCH(16,2),AFCH(16,2),VCKM(3,3),
     & GAMZP,GEV2NB,ALPHEM,PRSOF,CLSMR,
     & IPRINT,LRSUD,LWSUD,NCOLO,NFLAV,MODPDF,NSTRU,NZBIN,NBTRY,
     & NCTRY,NDTRY,NETRY,NSTRY,NGSPL,AZSOFT,AZSPIN,CLDIR,PRNDEC,ZPRIME,
     & HARDME,SOFTME,ISPAC,NOSPAC,
     & AUTPDF
C
C---PARTON SHOWER COMMON (SAME FORMAT AS /HEPEVT/)
      PARAMETER (NMXPAR=500)
      COMMON/HWPART/NEVPAR,NPAR,ISTPAR(NMXPAR),IDPAR(NMXPAR),
     & JMOPAR(2,NMXPAR),JDAPAR(2,NMXPAR),PPAR(5,NMXPAR),VPAR(4,NMXPAR)
C---PARTON POLARIZATION COMMON
      COMMON/HWPARP/PHIPAR(2,NMXPAR),DECPAR(2,NMXPAR),RHOPAR(2,NMXPAR),
     & TMPAR(NMXPAR)
C---ELECTROWEAK BOSON COMMON
      PARAMETER (MODMAX=5)
      COMMON/HWBOSC/ALPFAC,BRHIG(12),ENHANC(12),GAMMAX,RHOHEP(3,NMXHEP),
     &  MODBOS(MODMAX),IOPHIG
C---PARTON COLOUR COMMON:
C   JCOPAR(1,*) = COLOUR MOTHER
C   JCOPAR(2,*) = ANTICOLOUR MOTHER
C   JCOPAR(3,*) = COLOUR DAUGHTER
C   JCOPAR(4,*) = ANTICOLOUR DAUGHTER
      COMMON/HWPARC/JCOPAR(4,NMXPAR)
C
C---OTHER HERWIG BRANCHING, EVENT AND HARD SUBPROCESS COMMON
      COMMON/HWBRCH/XFACT,PTINT(3,2),HARDST,NSPAC(7),INHAD,JNHAD,FROST,
     & BREIT,USECMF
      COMMON/HWEVNT/EVWGT,AVWGT,WGTMAX,WGTSUM,WSQSUM,WBIGST,TLOUT,
     & NRN(2),MAXER,NUMER,NUMERU,MAXPR,LWEVT,ISTAT,IERROR,NOWGT,NWGTS,
     & IDHW(NMXHEP),GENSOF
      COMMON/HWHARD/YJMIN,YJMAX,PTMIN,PTMAX,PTPOW,EMMIN,EMMAX,EMPOW,
     & Q2MIN,Q2MAX,Q2POW,Q2WWMN,Q2WWMX,THMAX,QLIM,XXMIN,XLMIN,ZJMAX,
     & YBMIN,YBMAX,EMSCA,EMLST,COSTH,CTMAX,GPOLN,GCOEF(7),XX(2),PHOMAS,
     & DISF(13,2),TQWT,CLQ(7,6),MAPQ(6),EPOLN(3),PPOLN(3),COSS,SINS,
     & IBSH,IBRN(2),IPRO,IFLMIN,IFLMAX,MAXFL,IDCMF,IHPRO,
     & IDN(10),ICO(10),GENEV,FSTEVT,FSTWGT,BGSHAT,HVFCEN,
     & TPOL,IAPHIG
C---UTILITIES COMMON
      COMMON/HWUCLU/RESN(12,12),RMIN(12,12),LOCN(12,12)
      COMMON/HWUFHV/FBTM(6,2),FTOP(6,2),FHVY(6,2),BDECAY
      COMMON/HWUNAM/RNAME(264)
      COMMON/HWUPDT/RMASS(264),BFRAC(460),CMMOM(460),ETAMIX,IDPDG(264),
     & ICHRG(264),MADDR(264),MODES(264),MODEF(264),IDPRO(3,460),NRES
C---MAX NUMBER OF ENTRIES IN LOOKUP TABLES OF SUDAKOV FORM FACTORS
      PARAMETER (NMXSUD=1024)
      COMMON/HWUSUD/ACCUR,QEV(NMXSUD,6),SUD(NMXSUD,6),INTER,NQEV,NSUD,
     & SUDORD
      COMMON/HWUWTS/VECWT,TENWT,DECWT,QWT(3),PWT(12),SWT(264),
     & SWTEF(264),RESWT(264)
      INTEGER NMXJET
      PARAMETER (NMXJET=200)

 ----------------------------------------------------------------------

                    ****** 8. FORM FACTOR FILE******

   HERWIG uses look-up tables of Sudakov form factors for the evolution
   of initial-  and final-state parton showers.  These can be read from
   an input file  rather than being recomputed each time.  The reading,
   writing and computing of form factor tables is controlled by integer
   parameters LRSUD and LWSUD:

      LRSUD = N>0   Read form factors for this run from unit N
      LRSUD = 0     Compute new form factor tables for this run
      LRSUD < 0     Form factor tables are already loaded
      LWSUD = N>0   Write form factors on unit N for future use
      LWSUD = 0     Do not write new form factor tables

   The option LRSUD<0 allows the program to be initialized several times
   in the same run (e.g. to generate various event types) without recom-
   puting or rereading form factors.

   N.B. The Sudakov form factors depend on the parameters QCDLAM, VQCUT,
   VGCUT, NCOLO, NFLAV, NAFLA, RMASS(13) and RMASS(i) for i=1,...,NFLAV.
   Consequently form factor tables  MUST be recomputed every time any of
   these  parameters  is  changed.   From  version  5.1  onwards,  these
   parameters are written/read  with the  form factor tables  and checks
   are performed to ensure consistency.

   The parton  showering  algorithm  uses  the  two-loop  alpha_s,  with
   matching at each flavour threshold. However, the Sudakov table can be
   computed with either the one-loop or two-loop form,  according to the
   variable SUDORD  (= 1 or 2 respectively, DEFAULT=1).  If SUDORD=1 the
   two-loop value is  recovered using the  veto algorithm in the shower,
   whereas if SUDORD=2 no vetoes  are used in the final-state evolution.
   This means  that the relative weight of any shower  configuration can
   be calculated in a closed form,  hence that showers  can be `forced'.

   To next-to-leading order  the two  possibilities should be identical,
   but they  differ at beyond-NLO,  so some results may change a little.
   The most noticeable difference is that the form factor  table takes a
   factor of about five times longer to compute with SUDORD=2 than 1.
 ----------------------------------------------------------------------

                    ******** 9. EVENT DATA********

   /HEPEVT/ is the standard common block containing current event data:

   NEVHEP      - event number
   NHEP        - number of entries for this event
   ISTHEP(I)   - status of entry I (see below)
   IDHEP(I)    - identity of entry I (Particle Data Group code)
   JMOHEP(1,I) - pointer to  first mother of entry I (see below)
   JMOHEP(2,I) - pointer to second mother of entry I (see below)
   JDAHEP(1,I) - pointer to first daughter of entry I (see below)
   JDAHEP(2,I) - pointer to  last daughter of entry I (see below)
   PHEP(*,I)   - (Px,Py,Pz,E,M) of entry I: M=sign(sqrt(abs(m**2)),m**2)
   VHEP(*,I)   - (x,y,z,t) of prod'n vertex of entry I (not yet used)

   All momenta are  given in the  laboratory frame,  in which  the input
   beam momenta are PBEAM1 and PBEAM2 as specified by the user and point
   along the +z and -z directions respectively.  Final  state  particles
   have ISTHEP(I) = 1.  See the next Section for a  complete list of the
   special status codes used by HERWIG.

   The identity codes IDHEP are as recommended by the LEP Working Group,
   i.e. as defined by the Particle Data Group plus the following:

  * IDHEP = 91 for clusters, 94 for jets, 0 for others with no PDG code.

   (HERWIG also has its own internal identity codes  IDHW(I),  stored in
   /HWEVNT/. The utility subroutine HWUIDT translates between HERWIG and
   PDG identity codes.  See Sect. 16 for further details.)

   The  mother/daughter  pointers are standard,  except that JMOHEP(2,I)
   and  JDAHEP(2,I) for a  PARTON are its  COLOUR  mother  and daughter,
   i.e., the partons to which its  colour and  anticolour are connected,
   respectively.  For this purpose the  primary partons from a hard sub-
   process are all  regarded as outgoing  (see examples in Sects. 13, 16
   and 19).  Since quarks  have no  anticolour,  JDAHEP(2,I)  is used to
   point to  its FLAVOUR partner.  Similarly for JMOHEP(2,I) in the case
   of an antiquark.

   In addition to entries representing partons, particles, clusters etc,
   /HEPEVT/ contains purely informational entries representing the total
   c.m. momentum,  hard and soft  subprocess momenta, etc.  See Sect. 10
   for the corresponding status codes.

   Information  from  all  stages  of event  processing  is  retained in
   /HEPEVT/ so the same particle may appear several times with different
   status codes. For example, an outgoing parton from a  hard scattering
   (entered initially with status 113 or 114) will appear after process-
   ing as an on-mass-shell parton before QCD branching (status 123,124),
   an off-mass-shell entry representing the flavour and momentum  of the
   outgoing  jet (status 143,144), and a jet constituent (157). It might
   also appear again in  other contexts,  e.g. as a spectator in a heavy
   flavour decay (status 154,160).

   Incoming partons  (entered with status  111, 112, changed to 121, 122
   after branching) give rise to spacelike jets (status 141,142, m**2<0,
   indicated by PHEP(5,IHEP)<0)  due to the loss of momentum via initial
   state  bremsstrahlung.  The  same  applies  in principle  to incoming
   leptons, but QED radiative corrections are not yet included.

   Each  parton jet  begins  with a  status 141-144 jet entry giving the
   total flavour and  momentum of the jet.  The first  mother pointer of
   this entry gives the  location of the  parent hard parton,  while the
   second gives that of the subprocess  c.m. momentum.  If QCD branching
   has occurred,  this is  followed by a  lightlike  CONE  entry,  which
   fixes the angular  extent of  the jet  and its  azimuthal orientation
   relative to the parton with which it interferes. The interfering par-
   ton is listed as the second mother of the cone.  Next come the actual
   constituents of the jet.  If no branching  has occurred,  there is no
   cone and the single jet constituent is the same as the jet.
   -----------------------------------------------------------------------

                    *******10. STATUS CODES*******

   A complete list of currently-used HERWIG status codes is given below.
   Many are used only in  intermediate stages of  event processing.  The
   most important for users are probably 1 (final-state particle), 101-3
   (initial  state), 141-4 (jets), and 199 (decayed  b-  and t-flavoured
   hadrons).

   The event status ISTAT in common /HWEVNT/ is roughly ISTHEP-100 where
   ISTHEP  is the status of entries being processed.  However, ISTAT=100
   for completed events.

                 +------+------------------------------+
                 |ISTHEP|         Description          |
                 +------+------------------------------+
                 |   1  |  final state particle        |
                 |   2  |  parton before hadronization |
                 |   3  |  documentation line          |
                 +------+------------------------------+
                 | 100  |  cone limiting jet evolution |
                 | 101  | `beam'   (beam 1)            |
                 | 102  | `target' (beam 2)            |
                 | 103  |  overall centre of mass      |
                 +------+------------------------------+
                 | 110  | unprocessed hard process c.m.|
                 | 111  |      "      beam parton      |
                 | 112  |      "      target parton    |
                 | 113  |      "      outgoing parton 3|
                 | 114  |      "      outgoing parton 4|
                 | 115  |      "      spectator parton |
                 +------+------------------------------+
                 |120-25| as 110-15, after processing  |
                 +------+------------------------------+
                 | 130  | lepton in jet (unboosted)    |
                 |131-34| as 141-44, unboosted to c.m. |
                 | 135  | spacelike parton (beam, unb.)|
                 | 136  | spacelike parton (target,unb)|
                 | 137  | spectator (beam, unboosted)  |
                 | 138  | spectator (target, unb.)     |
                 | 139  | parton from branching (unb.) |
                 | 140  | parton from g splitting (unb)|
                 +------+------------------------------+
                 |141-44| jet from parton type 111-14  |
                 |145-50| as 135-40 boosted, unclust'd |
                 +------+------------------------------+
                 | 151  | as 159, not yet clustered    |
                 | 152  | as 160,  "   "      "        |
                 | 153  | spectator from beam          |
                 | 154  | spectator from target        |
                 | 155  | heavy quark before decay     |
                 | 156  | spectator before heavy decay |
                 | 157  | parton from QCD branching    |
                 | 158  | parton after gluon splitting |
                 | 159  | parton from cluster splitting|
                 | 160  | spectator after heavy decay  |
                 +------+------------------------------+
                 | 161  | beam spect.after gl.splitting|
                 | 162  | targ.spect.after gl.splitting|
                 | 163  | other cluster bef. soft proc.|
                 | 164  | beam cluster before soft proc|
                 | 165  | targ.cluster before soft proc|
                 | 167  | unhadronized beam cluster    |
                 | 168  | unhadronized target cluster  |
                 +------+------------------------------+
                 | 170  | soft process centre of mass  |
                 | 171  | soft cluster (beam, unhadr'd)|
                 | 172  | soft cluster (target,  "    )|
                 | 173  | soft cluster (other,   "    )|
                 +------+------------------------------+
                 | 181  | beam cluster  (no soft proc.)|
                 | 182  | target cluster( "   "    "  )|
                 | 183  | hard proc. clus. (hadronized)|
                 | 184  | soft cluster (beam,    "    )|
                 | 185  | soft cluster (target,  "    )|
                 | 186  | soft cluster (other,   "    )|
                 +------+------------------------------+
                 |190-93| as 195-98, before decays     |
                 | 195  | direct unstable non-hadron   |
                 | 196  | dir.unst. hadron (1-body cl.)|
                 | 197  | dir.unst. hadron (2-body cl.)|
                 | 198  | indir.unst. hadron or lepton |
                 | 199  | decayed heavy flavour hadron |
                 +------+------------------------------+
 -----------------------------------------------------------------------

                     ******11. EVENT WEIGHTS******

   The  default is  to generate  unweighted events  (EVWGT=AVWGT).  Then
   event distributions are generated by computing a  weight proportional
   to the cross section  and comparing it with a random number times the
   maximum weight.  Set WGTMAX to the maximum weight, or to zero for the
   program to compute it.  If a weight greater than  WGTMAX is generated
   during execution, a warning is printed and WGTMAX is reset. Similarly
   if the  efficiency  is too low  (WGTMAX too large).  If these  errors
   occur  too often,  output  event  distributions  could be  distorted.

   To generate  weighted  events,  set NOWGT=.FALSE. in common /HWEVNT/.

   In QCD hard scattering and heavy flavour and direct photon production
   (IPROC = 1500 to 1800) the transverse energy distribution of weighted
   events (or the efficiency for unweighted  events) can be varied using
   the parameters PTMIN, PTMAX and PTPOW.

   Similarly in  Drell-Yan processes (IPROC = 13**) the lepton pair mass
   distribution is controlled by the parameters  EMMIN, EMMAX and EMPOW,
   and in  deep  inelastic  scattering the  Q**2 distribution  is set by
   Q2MIN, Q2MAX and Q2POW.

   Data on weights  generated are output at the end of the run. The mean
   weight is an  estimate of the cross section (in nanobarns) integrated
   over the region used for event generation.

   N.B.  The  mean weight  is the  sum of  weights  divided by the total
   number  of  WEIGHTS  generated,  not  the  total  number  of  EVENTS.
 -----------------------------------------------------------------------

                  ****12. HEAVY FLAVOUR DECAYS***

   Heavy quark decays are treated as  secondary hard  subprocesses.  Top
   quarks can decay either  before or after hadronization,  depending on
   the value of the  logical variable  DECAY  returned by the subroutine
   HWDTOP.  At present decay occurs  before hadronization (DECAY=.TRUE.)
   if the top mass is above 120 GeV (default=100 GeV).  Any hypothetical
   heavier quarks  always decay  before hadronization.  Top- and bottom-
   flavoured hadrons are split into  collinear heavy quark and spectator
   and the former decays independently.  After decay, parton showers may
   be  generated  from  coloured  decay products, in the usual way.  See
   Nucl. Phys. B330 (1990) 261  for details  of the  treatment of colour
   coherence in these showers.

   Users may  wish to  change the  decay fractions for heavy quarks, for
   example to force a leptonic decay in every event. This can be done by
   modifying the contents of  COMMON/HWUFHV/:  FBTM(1,1), FBTM(2,1),...,
   FBTM(6,1) are the b-quark decay fractions into the 6 doublets  (d,u),
   (s,c),(b,t),(e,nue),(mu,numu),(tau,nutau) respectively. FBTM(1,2) etc
   are the corresponding b-bar fractions.  Thus to get all  B hadrons to
   decay to muons,  while keeping the default decay  fractions for B-bar
   hadrons,  one would set FBTM(J,1)=0 for J.NE.5 and FBTM(5,1)=1, with-
   out changing  FBTM(J,2).  FTOP is the corresponding array for the top
   quark, while FHVY is for quarks heavier than top.  All  these  quant-
   ities  can  be  changed  from  event to event.
 -----------------------------------------------------------------------

                     ***13. QCD HARD SUBPROCESSES***

    At present only 2->2 subprocesses are implemented. They are class-
    ified as shown below.

            +-----+------------------------------+---------+
            |IHPRO|   Process 1 + 2 -> 3 + 4     |Col/F.Con|
            +-----+------------------------------+---------+
            |  1  | q + q        -> q + q        | 3 4 2 1 |
            |  2  | q + q        -> q + q        | 4 3 1 2 |
            |  3  | q + q'       -> q + q'       | 3 4 2 1 |
            |  4  | q + qbar     -> q'+ qbar'    | 2 4 1 3 |
            |  5  | q + qbar     -> q + qbar     | 3 1 4 2 |
            |  6  | q + qbar     -> q + qbar     | 2 4 1 3 |
            |  7  | q + qbar     -> g + g        | 2 4 1 3 |
            |  8  | q + qbar     -> g + g        | 2 3 4 1 |
            |  9  | q + qbar'    -> q + qbar'    | 3 1 4 2 |
            | 10  | q + g        -> q + g        | 3 1 4 2 |
            | 11  | q + g        -> q + g        | 3 4 2 1 |
            | 12  | qbar + q     -> qbar' +q'    | 3 1 4 2 |
            | 13  | qbar + q     -> qbar + q     | 2 4 1 3 |
            | 14  | qbar + q     -> qbar + q     | 3 1 4 2 |
            | 15  | qbar + q     -> g + g        | 3 1 4 2 |
            | 16  | qbar + q     -> g + g        | 4 1 2 3 |
            | 17  | qbar + q'    -> qbar + q'    | 2 4 1 3 |
            | 18  | qbar + qbar  -> qbar + qbar  | 4 3 1 2 |
            | 19  | qbar + qbar  -> qbar + qbar  | 3 4 2 1 |
            | 20  | qbar + qbar' -> qbar + qbar' | 4 3 1 2 |
            | 21  | qbar + g     -> qbar + g     | 2 4 1 3 |
            | 22  | qbar + g     -> qbar + g     | 4 3 1 2 |
            | 23  | g + q        -> g + q        | 2 4 1 3 |
            | 24  | g + q        -> g + q        | 3 4 2 1 |
            | 25  | g + qbar     -> g + qbar     | 3 1 4 2 |
            | 26  | g + qbar     -> g + qbar     | 4 3 1 2 |
            | 27  | g + g        -> q + qbar     | 2 4 1 3 |
            | 28  | g + g        -> q + qbar     | 4 1 2 3 |
            | 29  | g + g        -> g + g        | 4 1 2 3 |
            | 30  | g + g        -> g + g        | 4 3 1 2 |
            | 31  | g + g        -> g + g        | 2 4 1 3 |
            +-----+------------------------------+---------+

   `Col/F.Con'  refers  to the  colour/flavour  connections  between the
   partons:`I J K L' means that the colour of parton 1 comes from parton
   I, that of 2 from J, etc.  For antiquarks, which have no colour (only
   anticolour),  the label shows  instead to which parton the flavour is
   connected.  For this colour/flavour labelling all partons are defined
   as outgoing.  Thus, for example,  process  10 has colour  connections
   3 1 4 2, corresponding to the colour flow diagram:

                           1 -->--+ +-->-- 3
                                  | |
                                  | |
                             --<--+ +--<--
                           2 -->------->-- 4

   When different colour flows are possible, they are listed as separate
   subprocesses.  This separation  is not exact  but is  normally a good
   approximation.  The sum of the colour flows is the exact lowest-order
   cross section.
 -----------------------------------------------------------------------

                ***14. QCD DIRECT PHOTON SUBPROCESSES***

            +-----+------------------------------+---------+
            |IHPRO|   Process 1 + 2 -> 3 + 4     |Col/F.Con|
            +-----+------------------------------+---------+
            | 41  | q + qbar     -> g + photon   | 2 3 1 4 |
            | 42  | q + gluon    -> q + photon   | 3 1 2 4 |
            | 43  | qbar + q     -> g + photon   | 3 1 2 4 |
            | 44  | qbar + gluon -> qbar + photon| 2 3 1 4 |
            | 45  | gluon + q    -> q    + photon| 2 3 1 4 |
            | 46  | gluon + qbar -> qbar + photon| 3 1 2 4 |
            | 47  | gluon + gluon-> gluon+ photon| 2 3 1 4 |
            +-----+------------------------------+---------+
            | 51  | photon+ q    -> gluon+ q     | 1 4 2 3 |
            | 52  | photon+ qbar -> gluon+ qbar  | 1 3 4 2 |
            | 53  | photon+ gluon-> q    + qbar  | 1 4 2 3 |
            +-----+------------------------------+---------+
            | 61  | q + qbar     -> photon+photon| 2 1 3 4 |
            | 62  | qbar + q     -> photon+photon| 2 1 3 4 |
            | 63  | gluon + gluon-> photon+photon| 2 1 3 4 |
            +-----+------------------------------+---------+
            | 71  | photon+ q    -> M(S=0) +q'   | 1 4 3 2 |
            | 72  | photon+ q    -> M(S=1)L+q'   | 1 4 3 2 |
            | 73  | photon+ q    -> M(S=1)T+q'   | 1 4 3 2 |
            | 74  | photon+ qbar -> M(S=0) +qbar'| 1 4 3 2 |
            | 75  | photon+ qbar -> M(S=1)L+qbar'| 1 4 3 2 |
            | 76  | photon+ qbar -> M(S=1)T+qbar'| 1 4 3 2 |
            +-----+------------------------------+---------+

   N.B. The photon is connected to itself.
 -----------------------------------------------------------------------

                ***15. QCD HIGGS PLUS JET SUBPROCESSES***

            +-----+------------------------------+---------+
            |IHPRO|   Process 1 + 2 -> 3 + 4     |Col/F.Con|
            +-----+------------------------------+---------+
            | 81  | q    + qbar  -> g    + H     | 2 3 1 4 |
            | 82  | q    + g     -> q    + H     | 3 1 2 4 |
            | 83  | qbar + q     -> g    + H     | 3 1 2 4 |
            | 84  | qbar + g     -> qbar + H     | 2 3 1 4 |
            | 85  | g    + q     -> q    + H     | 2 3 1 4 |
            | 86  | g    + qbar  -> qbar + H     | 3 1 2 4 |
            | 87  | g    + g     -> g    + H     | 2 3 1 4 |
            +-----+------------------------------+---------+

   N.B. The Higgs is connected to itself.

 -----------------------------------------------------------------------
                ******16. ELECTROWEAK SUBPROCESSES******

   HERWIG  generates  Higgs bosons  through  gluon-gluon/quark-antiquark
   fusion,  and W fusion in hadron-hadron collisions  (IPROC=1600+ID and
   1900+ID),  in lepton-lepton  collisions  through  the Bjorken process
   (that is, Z(*)->Z(*)H  with one or both Zs  off-shell)  and  W fusion
   (IPROC=300+ID and 400+ID),  and in lepton-hadron collisions through W
   fusion (IPROC=9500+ID).  Each process  is generated  according to the
   exact  leading  order matrix  element in the s-channel approximation.
   This results in  unitarity violation for  Mh >> Mw,  s >~ a few Mh^2,
   (where s=qh^2), so to regularize this,  the Mh*GAMH in the propagator
   can be replaced by SQRT(s)*GAMH(s). The variable IOPHIG controls this
   procedure:

       +------+------------------------------+-----------+
       |IOPHIG|   Choose s according to      | Reweight? |
       +------+------------------------------+-----------+
       |   0  | s^2 / ((s-Mh^2)^2 + Mh*GAMH) |    YES    |
       |   1  |  1  / ((s-Mh^2)^2 + Mh*GAMH) |    YES    |
       |   2  | s^2 / ((s-Mh^2)^2 + Mh*GAMH) |     NO    |
       |   3  |  1  / ((s-Mh^2)^2 + Mh*GAMH) |     NO    |
       +------+------------------------------+-----------+

   Where reweighting means weighting the distribution back to

                          SQRT(s) * GAMH(s)
                     ----------------------------
                     (s-Mh^2)^2 + SQRT(s)*GAMH(s)

   The default is IOPHIG=1.  The difference  between options  0 and 1 is
   purely  in the  weight  distribution  produced.  Options  2 and 3 are
   intended primarily for  users who wish to supply  their own unitarity
   conserving  reweighting  function at the point  indicated in  routine
   HWHIGM.  In all cases,  the distribution  is restricted  to the range
   [Mh-GAMMAX*GAMH , Mh+GAMMAX*GAMH].  GAMMAX defaults to 10, but in the
   (probably unphysical) region  Mh >~ 1TeV should be reduced to protect
   against poor weight distributions. These considerations do not affect
   the distribution noticably for  Mh <~ 500 GeV,  and GAMMAX can safely
   be increased if necessary.

   For each process, ID controls the Higgs decay: ID=1-6 for quarks, 7-9
   for leptons, 10/11 for WW/ZZ pairs,  and 12 for photons.  In addition
   ID=0 gives quarks of all flavours,  and ID=99  gives all decays.  For
   each process,  the average  event  weight  is the cross-section in nb
   times the branching  fraction  to the requested decay.  The branching
   ratios to quarks use the next-to-leading logarithm corrections, those
   to WW/ZZ pairs allow for one or both bosons off-shell. The amplitudes
   for all Higgs vertices are multiplied by the factor ENHANC(ID)  where
   ID is the same as in IPROC=300+ID except the gammagammaHiggs `vertex'
   which is calculated from ENHANC(6)  and ENHANC(10)  for the top and W
   loops.  This allows  the simulation  of any chargeless  scalar Higgs.
   Note however  that  pseudoscalar and charged Higgses,  and  processes
   involving more than one Higgs (eg the decay H-->hZ) are not included.

   Gauge bosons  are generated  through the  processes  of  W + 1 parton
   production in hadron-hadron  collisions,  and  WW  pair production in
   lepton-lepton collisions, as well as in the Higgs processes mentioned
   above.   In  all  cases  their  decay is controlled  by the  variable
   MODBOS(i). This controls the decay of the ith gauge boson per event:

       +---------+-----------------+-----------------+
       |MODBOS(i)|     W Decay     |     Z Decay     |
       +---------+-----------------+-----------------+
       |    0    |        all      |        all      |
       |    1    |       qqbar     |       qqbar     |
       |    2    |        enu      |       e+e-      |
       |    3    |        munu     |      mu+mu-     |
       |    4    |       taunu     |     tau+tau-    |
       |    5    |     enu & munu  |    ee & mumu    |
       |    6    |        all      |      nunu       |
       |    7    |        all      |     bbbar       |
       |   >7    |        all      |       all       |
       +---------+-----------------+-----------------+

   All  entries of  MODBOS  default to 0.   Bosons which are produced in
   pairs  (ie. from WW pair production, or Higgs decay)  are symmetrized
   in MODBOS(i)  and  MODBOS(i+1).  For processes which directly produce
   gauge bosons, the event weight includes the branching fraction to the
   requested decay,  but this is only true for Higgs production if decay
   to WW/ZZ is forced (ID=10/11) and not if ID=99. The spin-correlations
   in the decays are handled in one of two ways:
   (a) the diagonal  members of the  spin  density  matrix are stored in
       RHOHEP(i,IHEP),  where i=1,2,3 for helicity=i-2 in the centre-of-
       mass frame of their production,  for processes  where this matrix
       is diagonal (ie. there is no interference between spin states).
   (b) the  correlations  in the  decay  are  handled  directly  by  the
       production routine where (a) is not possible.
   In the case of  gamma gamma --> W W  the  decay correlations  are not
   correctly included: they currently decay isotropically.

   The electroweak vector boson--fermion coupling  constants are  stored
   in the arrays QFCH(I), VFCH(I,J) and AFCH(I,J) for the charge, vector
   and axial vector couplings to the neutral current respectively. These
   are given in the convention 
       V_f=(T_3/2-Qsin^2_W)/(cos_W sin_W);  A_f=T_3/(2 cos_W sin_W).
   In each case,
     I= 1- 6: d,u,s,c,b,t (quarks)
      =11-16: e,nu_e,mu,nu_mu,tau,nu_tau (leptons) (`I=IDHW-110')
     J=1 for minimal SM:
      =2 for Z' couplings (only included if ZPRIME=.TRUE.)
   Note that no universality is assumed -- couplings can be arbitrarily
   set for each fermion species separately.
   The quark mixing matrix  is stored in VCKM(K,L),  K=1,2,3 for u,c,t,
   L=1,2,3 for d,s,b.

   A running electromagnetic coupling constant is provided, HWUAEM(Q2).
   ALPHEM =1/137 provides the normalisation at the Thomson (Q2=0) limit
   and is used for all processes involving real photons.
   The electroweak coupling is calculated as,
                 g^2 = 4 PIFAC ALPHEM(Q2) / SWEIN,
   where Q2 is appropriate for the given process.
   Photon emission in parton showers,  and in the  `dead-zone'  in e+e-
   is enhanced by a factor of ALPFAC (default=1.).

 -----------------------------------------------------------------------

                *****17. INCLUDING NEW SUBPROCESSES*****

   It should not be difficult for users to include  further subprocesses
   in this version of the program if required.  The parton and hard sub-
   process 4-momenta,  masses and  identity codes  need to be entered in
   COMMON/HEPEVT/ with the appropriate status codes ISTHEP(I)=110-114 to
   tell the program which is which (see table in Sect. 10).  The colour/
   flavour structure should be specified by the second mother and daugh-
   ter pointers as explained in Sect. 13 (see also the sample output and
   guide, Sects. 18 and 19).

   Apart from the status codes ISTHEP, the HERWIG identity codes IDHW(I)
   in COMMON/HWEVNT/ also need  to be set correctly.  The IDHW codes can
   be listed in a run with  IPRINT=2:  the most important are the quarks
   1-6 (as IDHEP), antiquarks 7-12, gluon 13, overall c.m. 14, hard c.m.
   15, soft c.m. 16,  photon 59,  leptons 121-126,  antileptons 127-132.

   The  utility  subroutine  HWUIDT(IOPT,IPDG,IHWG,NAME)  is provided to
   translate between  Particle Data Group code  IPDG,  HERWIG code IHWG,
   and HERWIG  character*4 NAME,  with IOPT=1,2,3  depending on which of
   IPDG, IHWG and NAME is the input argument.

   Consider for example  the process of  virtual photon-gluon  fusion to
   make  b+bbar in  e p collisions.

       **** N.B. This process is now included as IPROC = 9102 ****

   We assume the user provides a subroutine to generate the momenta PHEP
   for the  hard  subprocess   e+g -> e+b+bbar.  The colour structure is

                        (e)4 ........... 7(e)
                                  :
                                  :
                                  +-->-- 8(b)
                                  |
                             -->--+
                        (g)5 --<-----<-- 9(bbar)

   Thus the momenta generated, together with those of the initial beams
   and the overall  centre of mass,  could be entered  in the following
   sequence:

             +----+--------+------+-----+------+------+----+
             |IHEP|  Entry |ISTHEP|IDHEP|JMOHEP|JDAHEP|IDHW|
             +----+--------+------+-----+------+------+----+
             |  1 | e beam |  101 |   11|  0  0|  0  0| 121|
             |  2 | p beam |  102 | 2212|  0  0|  0  0|  73|
             |  3 | ep c.m.|  103 |    0|  0  0|  0  0|  14|
             +----+--------+------+-----+------+------+----+
             |  4 | e in   |  111 |   11|  6  7|  0  7| 121|
             |  5 | gluon  |  112 |   21|  6  9|  0  8|  13|
             |  6 | hard cm|  110 |    0|  4  5|  7  9|  15|
             |  7 | e out  |  113 |   11|  6  4|  0  4| 121|
             |  8 | b      |  114 |    5|  6  5|  0  9|   5|
             |  9 | bbar   |  114 |   -5|  6  8|  0  5|  11|
             +----+--------+------+-----+------+------+----+

   Note that if there are more than two outgoing partons,  the first has
   status  113 and all the others 114.  Each parton has JMOHEP(1,I)=6 to
   indicate  the location of  the hard c.m.  for this subprocess,  while
   JMOHEP(2,I) gives the location of the colour mother (treating the in-
   coming gluon as outgoing) or the connected electron. JDAHEP(1,I) will
   be set by the jet generator  HWBGEN,  while JDAHEP(2,I) points to the
   anticolour mother (or connected electron). Finally the HERWIG identi-
   fiers IDHW(I) could be set to the indicated values by means of the
   translation subroutine HWUIDT as follows:

      CHARACTER*4 NAME
      .....
      NHEP=9
      IDHEP(1)=11
      IDHEP(2)=2212
      .....
      IDHEP(9)=-5
      DO 10 I=1,NHEP
   10 CALL HWUIDT(1,IDHEP(I),IDHW(I),NAME)
      IDHW(6)=15

   The last statement is needed because  IDPDG(I)=0  returns IDHW(I)=14.
   If subroutine HWBGEN is now called, it will find the coloured partons
   and generate QCD jets from them.  Subsequent calls to  HWCFOR etc can
   then be used to form clusters and hadronize them.

   If the  hard subprocess  routine is  called from  HWEPRO,  like those
   already provided, it should have two options controlled by the logic-
   al variable  GENEV  in  COMMON/HWHARD/.   For GENEV=.FALSE., an event
   weight  (normally the  cross section  in nanobarns)  is generated and
   stored as  EVWGT  in COMMON/HWEVNT/.  If this  weight is  accepted by
   HWEPRO, the subroutine is called a second time with  GENEV=.TRUE. and
   the corresponding  event data should  then be generated and stored as
   explained above.
 -----------------------------------------------------------------------

                     *****18. ERROR CONDITIONS*****

   Certain combinations of input parameters may lead to problems in exe-
   cution.  HERWIG  tries to  detect these and  print a warning.  Errors
   during  execution are dealt with by  HWWARN  which prints the calling
   subprogram and a code and takes  appropriate action.  In general, the
   larger  the code  the more serious  the problem.  Refer to the source
   code  to find  out why  HWWARN  was  called.  Events  can be rerun by
   setting the random number seeds  NRN to the values given in the error
   message or event dump,  and MAXWGT to the maximum weight  encountered
   in the run.  Contents of  /HEPEVT/  can by printed by calling HWUEPR,
   those of /HWPART/ (last parton shower) by HWUBPR.

   If WGTMAX is increased during event generation, so that this message
   is printed:
   HWWARN CALLED FROM SUBPROGRAM HWEPRO: CODE =   1
   EVENT      21:   SEEDS =  836291635 & 1823648329  WEIGHT = 0.3893E-08
   EVENT SURVIVES. EXECUTION CONTINUES
          NEW MAXIMUM WEIGHT = 0.428217360829367E-08
   then to regenerate any later events, WGTMAX must be set to the printed
   value, as well as setting NRN to the appropriate seeds.

   Examples of error messages:

   HWWARN CALLED FROM SUBPROGRAM HWSBRN: CODE = 101
   EVENT      31:   SEEDS =  422399901 &  771980111  WEIGHT = 0.3893E-08
   EVENT KILLED.   EXECUTION CONTINUES

   Spacelike (initial-state) parton branching had no phase space. This
   can happen due to cutoffs which are slightly different in the hard
   subprocess and the parton shower.
   Action taken:  program  throws away  this event and starts a new one.

   HWWARN CALLED FROM SUBPROGRAM HWCHAD: CODE = 102
   EVENT      51:   SEEDS = 1033784787 & 1428957533  WEIGHT = 0.3893E-08
   EVENT KILLED.   EXECUTION CONTINUES

   A cluster has been formed with too low a mass to represent any hadron
   of the correct flavour, and there is no colour-connected cluster from
   which the necessary additional mass could be transferred.
   Action taken:  program  throws away  this event and starts a new one.

   HWWARN CALLED FROM SUBPROGRAM HWUINE: CODE= 200
   EVENT SURVIVES.  RUN ENDS GRACEFULLY

   CPU time limit liable to be reached  before generating  MAXEV events.
   Action taken:  skips to terminal  calculations using existing events.

   HWWARN CALLED FROM SUBPROGRAM HWBSUD: CODE= 500
   RUN CANNOT CONTINUE

   The table of Sudakov form factors read on unit  LRSUD does not extend
   to  the  maximum  momentum  scale  (QLIM)  specified  for  this  run.
   Action taken: run aborted.  The user must either reduce  QLIM  or set
   LRSUD=0  to make a  bigger  table  (set  LWSUD  nonzero to write it).

   HWWARN CALLED FROM SUBPROGRAM HWBSUD: CODE= 515
   RUN CANNOT CONTINUE

   The table of  Sudakov form factors read on unit  LRSUD is for a diff-
   erent value of a relevant parameter  (in this case the b quark mass).
   Action taken: run aborted.  The user must make a new table (set LWSUD
   nonzero to write it).
 -----------------------------------------------------------------------

                      *****19. SAMPLE OUTPUT*****

   Below we give a  complete listing  of output  from version 5.1 of the
   program,  set up for  b quark  production in  pbar-p  collisions at a
   c.m. energy of  1.8 TeV.  Output from  version  5.8 is  very similar.
   The main features of the output are discussed in Sect. 19.

         HERWIG 5.1      APRIL   1991

         INPUT CONDITIONS FOR THIS RUN

         BEAM 1 (PBAR) MOMENTUM =    900.00
         BEAM 2 (P   ) MOMENTUM =    900.00
         PROCESS CODE (IPROC)   =    1705
         NUMBER OF FLAVOURS     =    6
         STRUCTURE FUNCTION SET =    3
         AZIM SPIN CORRELATIONS =    T
         AZIM SOFT CORRELATIONS =    T
         QCD LAMBDA (GEV)       =    0.2000
         DOWN     QUARK  MASS   =    0.3200
         UP       QUARK  MASS   =    0.3200
         STRANGE  QUARK  MASS   =    0.5000
         CHARMED  QUARK  MASS   =    1.8000
         BOTTOM   QUARK  MASS   =    5.2000
         TOP      QUARK  MASS   =  100.0000
         GLUON EFFECTIVE MASS   =    0.7500
         EXTRA SHOWER CUTOFF (Q)=    0.4800
         EXTRA SHOWER CUTOFF (G)=    0.0600
         CLUSTER MASS PARAMETER =    3.5000
         SPACELIKE EVOLN CUTOFF =    2.5000
         INTRINSIC P-TRAN (RMS) =    0.0000
         MIN P-TRAN FOR 2->2    =   10.0000
         MAX P-TRAN FOR 2->2    =  900.0000

         PDFLIB STRUCT FUNCTIONS NOT USED

         NO EVENTS WILL BE WRITTEN TO DISK
         READING SUDAKOV TABLE ON UNIT   77
         PARTICLE TYPE  21=PI0  SET STABLE

         INITIAL SEARCH FOR MAX WEIGHT

         PROCESS CODE IPROC =        1705
         RANDOM NO. SEED 1  =     1246579
                    SEED 2  =     8447766
         NUMBER OF SHOTS    =        2000
         NEW MAXIMUM WEIGHT =  0.3123E+05
         NEW MAXIMUM WEIGHT =  0.3883E+05
         NEW MAXIMUM WEIGHT =  0.5639E+05

         INITIAL SEARCH FINISHED

         OUTPUT ON ELEMENTARY PROCESS

         NUMBER OF EVENTS   =           0
         NUMBER OF WEIGHTS  =        2000
         MEAN VALUE OF WGT  =  0.2447E+04
         RMS SPREAD IN WGT  =  0.7210E+04
         ACTUAL MAX WEIGHT  =  0.5542E+05
         ASSUMED MAX WEIGHT =  0.5639E+05

         PROCESS CODE IPROC =        1705
         CROSS SECTION (PB) =2447328.6400
         ERROR IN C-S  (PB) = 161219.9097
         EFFICIENCY PERCENT =      4.3404

 EVENT      1:     900.00 GEV/C PBAR ON     900.00 GEV/C P     PROCESS:  1705

 SEEDS:      17673 &      63565   STATUS: 100  ERROR:   0  WEIGHT: 0.2447E+04

                           ---INITIAL STATE---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
   1 PBAR -2212 101   0   0   0   0    0.00    0.00   900.00   900.00    0.94
   2 P     2212 102   0   0   0   0    0.00    0.00  -900.00   900.00    0.94
   3 CMF      0 103   0   0   0   0    0.00    0.00     0.00  1800.00 1800.00

                          ---HARD SUBPROCESS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
   4 GLUE    21 121   6   7   9   5    0.00    0.00    49.00    49.00    0.75
   5 BBAR    -5 122   6   4  15   8    0.00    0.00    -5.19     7.35    5.20
   6 HARD     0 120   4   5   7   8    8.17   -5.11    43.81    57.17   35.45
   7 GLUE    21 123   6   8  21   4    5.97   11.07    40.40    42.32    0.75
   8 BBAR    -5 124   6   5  28   7   -5.97  -11.07     3.41    14.03    5.20

                          ---PARTON SHOWERS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
   9 GLUE    94 141   4   6  11  14    3.81    0.90    50.87    50.70   -5.67
  10 CONE     0 100   4   7   0   0    0.47    0.88     2.41     2.61    0.00
  11 GLUE    21   2   9  12  33  34   -1.23   -0.28    33.27    33.30    0.75
  12 GLUE    21   2   9  13  35  36   -1.81   -1.85    30.74    30.85    0.75
  13 DBAR    -1 157   9  14  84  56   -0.69    1.09    63.44    63.45    0.32
  14 UBUB -2203 155   9  49  69  13    0.00    0.00   626.16   626.16    0.64
  15 BBAR    94 142   5   6  17  20    4.36   -6.01    -7.06     6.46   -7.95
  16 CONE     0 100   5   4   0   0   -0.69   -0.72     1.70     1.97    0.00
  17 BOTM     5 157  15  51  70  32   -3.10    5.14   -63.03    63.53    5.20
  18 UD    2101 156  15  19  82  52    0.00    0.00  -527.92   527.92    0.64
  19 UP       2 157  15  53  71  18    0.61   -1.83  -178.83   178.84    0.32
  20 GLUE    21   2  15  33  37  38   -1.88    2.83   -80.06    80.14    0.75
  21 GLUE    94 143   7   6  23  27    9.16    4.95    34.61    37.96   11.59
  22 CONE     0 100   7   8   0   0   -0.34   -0.79     0.70     1.11    0.00
  23 GLUE    21   2  21  24  39  40    0.97    2.06    11.95    12.19    0.75
  24 SBAR    -3 157  21  25  76  40    0.62    0.41    12.20    12.23    0.50
  25 STRA     3 157  21  41  72  24    2.76    0.90     5.42     6.17    0.50
  26 GLUE    21   2  21  27  41  42    2.21    0.79     3.08     3.94    0.75
  27 GLUE    21   2  21  30  43  44    2.58    0.80     1.97     3.43    0.75
  28 BBAR    94 144   8   6  30  32   -0.99  -10.06     9.19    19.21   13.51
  29 CONE     0 100   8   7   0   0    0.22    0.90     0.51     1.05    0.00
  30 GLUE    21   2  28  31  45  46   -0.44    1.69     1.76     2.59    0.75
  31 GLUE    21   2  28  32  47  48    1.06    0.55     0.86     1.65    0.75
  32 BBAR    -5 157  28  17  80  48   -1.60  -12.30     6.57    14.97    5.20

                          ---GLUON SPLITTING---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  33 DBAR    -1 158   9  34  90  68   -0.18   -0.06     4.28     4.29    0.32
  34 DOWN     1 158   9  35  73  33   -0.87   -0.16    24.76    24.78    0.32
  35 DBAR    -1 158   9  36  73  34   -0.54   -0.43     9.16     9.19    0.32
  36 DOWN     1 158   9  55  74  35   -0.93   -1.03    16.12    16.18    0.32
  37 UBAR    -2 158  15  38  83  54   -0.76    1.26   -38.50    38.53    0.32
  38 UP       2 158  15  61  75  37   -0.59    0.81   -21.14    21.16    0.32
  39 UBAR    -2 158  21  40  81  50    0.55    1.27     8.00     8.12    0.32
  40 UP       2 158  21  24  76  39    0.41    0.75     3.78     3.89    0.32
  41 UBAR    -2 158  21  42  72  25    1.23    0.50     2.01     2.43    0.32
  42 UP       2 158  21  43  77  41    0.99    0.28     1.07     1.52    0.32
  43 UBAR    -2 158  21  44  77  42    0.69    0.30     0.66     1.05    0.32
  44 UP       2 158  21  45  78  43    1.90    0.50     1.31     2.38    0.32
  45 DBAR    -1 158  28  46  78  44   -0.23    1.19     1.00     1.60    0.32
  46 DOWN     1 158  28  47  79  45   -0.21    0.50     0.76     0.99    0.32
  47 DBAR    -1 158  28  48  79  46    0.72    0.52     0.54     1.09    0.32
  48 DOWN     1 158  28  32  80  47    0.34    0.04     0.32     0.57    0.32
  49 DBAR    -1 159   9  50  69  14    0.00    0.01    68.74    68.74    0.32
  50 DOWN     1 159  21  39  81  49    0.01    0.03    19.19    19.19    0.32
  51 DBAR    -1 159  15  52  70  17   -0.04    0.06    -8.67     8.68    0.32
  52 DOWN     1 159  15  18  82  51   -0.04    0.07    -7.69     7.69    0.32
  53 DBAR    -1 159  15  54  71  19   -0.04    0.02   -14.54    14.55    0.32
  54 DOWN     1 159  15  37  83  53    0.00   -0.08   -18.38    18.38    0.32
  55 DBAR    -1 159   9  56  74  36   -0.20   -0.10     6.72     6.73    0.32
  56 DOWN     1 159   9  13  84  55   -0.22   -0.15     6.51     6.53    0.32
  57 DBAR    -1 159  15  58  86  60   -0.02    0.00     0.29     0.43    0.32
  58 DOWN     1 159   9  65  85  57   -0.08    0.11    -2.97     2.99    0.32
  59 DBAR    -1 159  15  60  87  62   -0.01    0.00     0.12     0.34    0.32
  60 DOWN     1 159  15  57  86  59   -0.17    0.23    -6.07     6.09    0.32
  61 UBAR    -2 159  15  62  75  38   -0.06    0.09    -2.25     2.27    0.32
  62 UP       2 159  15  59  87  61   -0.04    0.05    -1.22     1.26    0.32
  63 UBAR    -2 159   9  64  89  66   -0.02    0.00     0.40     0.52    0.32
  64 UP       2 159   9  67  88  63   -0.02    0.02    -0.44     0.54    0.32
  65 SBAR    -3 159   9  66  85  58   -0.02    0.00     0.04     0.50    0.50
  66 STRA     3 159   9  63  89  65   -0.02    0.02    -0.47     0.69    0.50
  67 UBAR    -2 159   9  68  88  64   -0.01    0.00     0.10     0.33    0.32
  68 UP       2 159   9  33  90  67   -0.11   -0.04     2.48     2.50    0.32

                         ---CLUSTER FORMATION---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  69 CLUS    91 167  14  49 225   0    0.00    0.00   694.90   694.90    1.22
  70 CLUS    91 183  17  51  91  92   -3.14    5.21   -71.70    72.21    5.97
  71 CLUS    91 183  19  53  93  94    0.57   -1.82  -193.38   193.39    1.38
  72 CLUS    91 183  25  41  95  96    3.99    1.40     7.42     8.59    0.93
  73 CLUS    91 183  34  35  97  98   -1.41   -0.59    33.92    33.97    1.00
  74 CLUS    91 183  36  55  99 100   -1.13   -1.13    22.84    22.91    0.92
  75 CLUS    91 183  38  61 101 102   -0.65    0.90   -23.38    23.44    1.08
  76 CLUS    91 183  40  24 103 104    1.03    1.16    15.98    16.12    1.46
  77 CLUS    91 183  42  43 105 106    1.67    0.58     1.73     2.57    0.67
  78 CLUS    91 183  44  45 107 108    1.66    1.69     2.31     3.98    2.22
  79 CLUS    91 183  46  47 109 110    0.51    1.02     1.31     2.08    1.14
  80 CLUS    91 183  48  32 111 112   -1.26  -12.26     6.89    15.53    6.47
  81 CLUS    91 183  50  39 113 114    0.56    1.30    27.19    27.31    2.23
  82 CLUS    91 168  52  18 225   0   -0.04    0.07  -535.60   535.61    2.84
  83 CLUS    91 183  54  37 115 116   -0.76    1.18   -56.88    56.91    1.31
  84 CLUS    91 183  56  13 117 118   -0.92    0.94    69.95    69.98    1.45
  85 CLUS    91 183  58  65 119 120   -0.10    0.12    -2.93     3.49    1.89
  86 CLUS    91 183  60  57 121 122   -0.19    0.23    -5.79     6.52    2.99
  87 CLUS    91 183  62  59 123 124   -0.05    0.05    -1.10     1.61    1.17
  88 CLUS    91 183  64  67 125 126   -0.03    0.02    -0.34     0.88    0.81
  89 CLUS    91 183  66  63 127 128   -0.04    0.02    -0.07     1.20    1.20
  90 CLUS    91 183  68  33 129 130   -0.29   -0.10     6.75     6.79    0.66

                          ---CLUSTER DECAYS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  91 B-    -521 199  70  15 173 174   -2.32    4.11   -63.08    63.48    5.27
  92 PI+    211   1  70  15   0   0   -0.82    1.10    -8.62     8.73    0.14
  93 PI+    211   1  71  15   0   0   -0.22   -0.71  -113.64   113.64    0.14
  94 PI0    111   1  71  15   0   0    0.79   -1.11   -79.74    79.75    0.13
  95 K-    -321   1  72  21   0   0    2.50    0.83     5.24     5.88    0.49
  96 PI0    111   1  72  21   0   0    1.50    0.57     2.19     2.72    0.13
  97 RHO0   113 197  73   9 131 132   -1.26   -0.63    28.22    28.26    0.77
  98 PI0    111   1  73   9   0   0   -0.15    0.04     5.70     5.71    0.13
  99 PI0    111   1  74   9   0   0   -0.17   -0.10     3.32     3.33    0.13
 100 RHO0   113 197  74   9 133 134   -0.96   -1.03    19.52    19.58    0.77
 101 ETA    221 197  75  15 135 137   -0.57    0.18   -12.55    12.58    0.55
 102 PI0    111   1  75  15   0   0   -0.08    0.72   -10.83    10.86    0.13
 103 PI+    211   1  76  21   0   0    0.38   -0.04     5.48     5.50    0.14
 104 K*0    313 197  76  21 138 139    0.66    1.21    10.50    10.62    0.89
 105 PI+    211   1  77  21   0   0    0.92    0.38     0.56     1.15    0.14
 106 PI-   -211   1  77  21   0   0    0.75    0.20     1.17     1.41    0.14
 107 PI0    111   1  78  21   0   0    0.96    0.52     0.12     1.11    0.13
 108 A1+  20213 197  78  21 140 141    0.70    1.16     2.18     2.87    1.27
 109 ETA    221 197  79  28 142 144    0.28    0.39     0.76     1.06    0.55
 110 ETA    221 197  79  28 145 147    0.24    0.62     0.54     1.02    0.55
 111 PI-   -211   1  80  28   0   0    0.56   -3.35     1.41     3.68    0.14
 112 B+     521 199  80  28 175 176   -1.82   -8.92     5.47    11.86    5.27
 113 PI-   -211   1  81  21   0   0    1.07    0.70     8.59     8.69    0.14
 114 OMEG   223 197  81  21 148 150   -0.51    0.60    18.59    18.63    0.78
 115 K0     311 197  83  15 151 151   -0.71    1.02   -46.50    46.52    0.50
 116 K-    -321   1  83  15   0   0   -0.05    0.16   -10.38    10.39    0.49
 117 ETA    221 197  84   9 152 154   -0.53    0.30    39.53    39.54    0.55
 118 RHO0   113 197  84   9 155 156   -0.39    0.64    30.42    30.44    0.77
 119 K0     311 197  85   9 157 157    0.05    0.43    -0.41     0.78    0.50
 120 ETPS   331 197  85   9 158 159   -0.15   -0.31    -2.52     2.72    0.96
 121 DEL0  2114 197  86  15 160 161   -0.51    0.76    -2.22     2.70    1.23
 122 DLB0 -2114 197  86  15 162 163    0.32   -0.52    -3.57     3.82    1.23
 123 PI0    111   1  87  15   0   0    0.41    0.28    -0.89     1.03    0.13
 124 PI+    211   1  87  15   0   0   -0.46   -0.23    -0.21     0.58    0.14
 125 PI0    111   1  88   9   0   0    0.05   -0.11    -0.24     0.30    0.13
 126 ETA    221 197  88   9 164 166   -0.08    0.13    -0.11     0.58    0.55
 127 K-    -321   1  89   9   0   0   -0.42    0.28    -0.12     0.72    0.49
 128 PI0    111   1  89   9   0   0    0.38   -0.27     0.05     0.49    0.13
 129 PI0    111   1  90   9   0   0   -0.43   -0.02     3.06     3.09    0.13
 130 PI+    211   1  90   9   0   0    0.14   -0.07     3.70     3.70    0.14

                       ---STRONG HADRON DECAYS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 131 PI-   -211   1  97   9   0   0   -0.98   -0.63    16.58    16.62    0.14
 132 PI+    211   1  97   9   0   0   -0.28    0.00    11.64    11.64    0.14
 133 PI-   -211   1 100   9   0   0   -0.23   -0.10     7.80     7.80    0.14
 134 PI+    211   1 100   9   0   0   -0.73   -0.93    11.72    11.78    0.14
 135 PI0    111   1 101  15   0   0   -0.32    0.13    -3.90     3.91    0.13
 136 PI0    111   1 101  15   0   0   -0.07    0.04    -3.64     3.64    0.13
 137 PI0    111   1 101  15   0   0   -0.18    0.01    -5.02     5.02    0.13
 138 PI-   -211   1 104  21   0   0    0.24    0.83     6.31     6.37    0.14
 139 K+     321   1 104  21   0   0    0.42    0.37     4.18     4.25    0.49
 140 PI+    211   1 108  21   0   0    0.64    0.42     0.74     1.07    0.14
 141 RHO0   113 198 108  21 167 168    0.06    0.74     1.45     1.80    0.77
 142 PI0    111   1 109  28   0   0    0.06    0.27     0.26     0.40    0.13
 143 PI-   -211   1 109  28   0   0    0.12   -0.03     0.25     0.31    0.14
 144 PI+    211   1 109  28   0   0    0.10    0.15     0.26     0.35    0.14
 145 PI0    111   1 110  28   0   0    0.10    0.32     0.35     0.50    0.13
 146 PI0    111   1 110  28   0   0   -0.02    0.16     0.15     0.26    0.13
 147 PI0    111   1 110  28   0   0    0.16    0.15     0.04     0.26    0.13
 148 PI0    111   1 114  21   0   0   -0.24    0.35    11.48    11.48    0.13
 149 PI-   -211   1 114  21   0   0   -0.30    0.28     5.78     5.80    0.14
 150 PI+    211   1 114  21   0   0    0.04   -0.03     1.33     1.34    0.14
 151 K0L    130   1 115  15   0   0   -0.71    1.02   -46.50    46.52    0.50
 152 PI0    111   1 117   9   0   0   -0.06    0.04     4.66     4.66    0.13
 153 PI0    111   1 117   9   0   0   -0.35    0.08    23.42    23.43    0.13
 154 PI0    111   1 117   9   0   0   -0.12    0.18    11.45    11.45    0.13
 155 PI-   -211   1 118   9   0   0   -0.01    0.28    21.64    21.65    0.14
 156 PI+    211   1 118   9   0   0   -0.38    0.37     8.78     8.80    0.14
 157 K0S    310 198 119   9 169 170    0.05    0.43    -0.41     0.78    0.50
 158 GAMA    22   1 120   9   0   0   -0.03   -0.02     0.02     0.04    0.00
 159 RHO0   113 198 120   9 171 172   -0.12   -0.29    -2.54     2.67    0.77
 160 PI-   -211   1 121  15   0   0    0.02    0.01    -0.59     0.60    0.14
 161 P     2212   1 121  15   0   0   -0.53    0.74    -1.63     2.09    0.94
 162 PI0    111   1 122  15   0   0   -0.13    0.03    -0.58     0.61    0.13
 163 NBAR -2112   1 122  15   0   0    0.45   -0.56    -2.99     3.22    0.94
 164 PI0    111   1 126   9   0   0   -0.06   -0.07    -0.06     0.18    0.13
 165 PI0    111   1 126   9   0   0   -0.08    0.01     0.01     0.16    0.13
 166 PI0    111   1 126   9   0   0    0.05    0.19    -0.06     0.25    0.13
 167 PI-   -211   1 141  21   0   0    0.22    0.55     1.38     1.51    0.14
 168 PI+    211   1 141  21   0   0   -0.15    0.19     0.07     0.29    0.14
 169 PI-   -211   1 157   9   0   0    0.16    0.37    -0.14     0.44    0.14
 170 PI+    211   1 157   9   0   0   -0.10    0.06    -0.28     0.33    0.14
 171 PI-   -211   1 159   9   0   0    0.01    0.07    -1.95     1.96    0.14
 172 PI+    211   1 159   9   0   0   -0.14   -0.36    -0.59     0.72    0.14

                       ---HEAVY FLAVOUR DECAYS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 173 BOTM     5 153  91 174 177 179   -2.18    3.86   -59.25    59.62    4.95
 174 UBAR    -2 125  91 179 183 179   -0.14    0.25    -3.83     3.85    0.32
 175 UP       2 125 112 182 184 182   -0.11   -0.54     0.33     0.72    0.32
 176 BBAR    -5 153 112 175 180 182   -1.71   -8.37     5.14    11.14    4.95
 177 UBAR    -2 123 173 178 185 178    0.46    0.82    -8.43     8.49    0.32
 178 DOWN     1 124 173 177 187 177    0.55    1.58   -16.23    16.32    0.32
 179 CHRM     4 124 173 173 189 173   -3.19    1.47   -34.60    34.82    1.80
 180 UP       2 123 176 181 191 181   -0.35   -0.50    -0.24     0.73    0.32
 181 DBAR    -1 124 176 180 193 180   -1.73   -3.45     3.62     5.30    0.32
 182 CBAR    -4 124 176 176 195 176    0.37   -4.43     1.77     5.11    1.80
 183 UBAR    -2 160 174 190 199 190   -0.14    0.25    -3.83     3.85    0.32
 184 UP       2 160 175 196 197 196   -0.11   -0.54     0.33     0.72    0.32

                          ---PARTON SHOWERS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 185 UBAR    94 143 177 173 186 186    0.46    0.82    -8.43     8.49    0.32
 186 UBAR    -2 157 185 188 198 188    0.46    0.82    -8.43     8.49    0.32
 187 DOWN    94 144 178 173 188 188    0.55    1.58   -16.23    16.32    0.32
 188 DOWN     1 157 187 186 198 186    0.55    1.58   -16.23    16.32    0.32
 189 CHRM    94 144 179 173 190 190   -3.19    1.47   -34.60    34.82    1.80
 190 CHRM     4 157 189 183 199 183   -3.19    1.47   -34.60    34.82    1.80
 191 UP      94 143 180 176 192 192   -0.35   -0.50    -0.24     0.73    0.32
 192 UP       2 157 191 194 200 194   -0.35   -0.50    -0.24     0.73    0.32
 193 DBAR    94 144 181 176 194 194   -1.73   -3.45     3.62     5.30    0.32
 194 DBAR    -1 157 193 192 200 192   -1.73   -3.45     3.62     5.30    0.32
 195 CBAR    94 144 182 176 196 196    0.37   -4.43     1.77     5.11    1.80
 196 CBAR    -4 157 195 184 197 184    0.37   -4.43     1.77     5.11    1.80

                         ---CLUSTER FORMATION---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 197 CLUS    91 183 184 196 201 202    0.26   -4.97     2.10     5.83    2.19
 198 CLUS    91 183 188 186 203 204    1.02    2.39   -24.65    24.80    0.72
 199 CLUS    91 183 190 183 205 206   -3.33    1.72   -38.43    38.68    2.26
 200 CLUS    91 183 192 194 207 208   -2.08   -3.95     3.38     6.03    2.25

                          ---CLUSTER DECAYS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 201 PI0    111   1 197 175   0   0    0.05   -0.25     0.22     0.36    0.13
 202 DC*B  -423 197 197 175 209 210    0.21   -4.72     1.88     5.47    2.01
 203 PI0    111   1 198 187   0   0    0.99    2.32   -23.61    23.75    0.13
 204 PI-   -211   1 198 187   0   0    0.03    0.07    -1.04     1.05    0.14
 205 DC*+   413 197 199 189 211 212   -3.27    1.70   -36.09    36.33    2.01
 206 PI-   -211   1 199 189   0   0   -0.06    0.02    -2.34     2.34    0.14
 207 N     2112   1 200 191   0   0   -0.86   -1.96     1.85     2.98    0.94
 208 DLB+ -1114 197 200 191 213 214   -1.22   -1.99     1.52     3.05    1.23

                       ---STRONG HADRON DECAYS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 209 DCBR  -421 198 202 175 215 216    0.09   -4.58     1.85     5.28    1.86
 210 GAMA    22   1 202 175   0   0    0.12   -0.14     0.03     0.19    0.00
 211 DC0    421 198 205 189 217 219   -2.97    1.54   -32.84    33.07    1.86
 212 PI+    211   1 205 189   0   0   -0.30    0.15    -3.25     3.27    0.14
 213 PI+    211   1 208 191   0   0   -0.29   -0.20     0.41     0.57    0.14
 214 NBAR -2112   1 208 191   0   0   -0.93   -1.79     1.11     2.48    0.94
 215 K0     311 198 209 175 220 220   -0.10   -0.24     0.13     0.58    0.50
 216 ETA    221 198 209 175 221 222    0.20   -4.34     1.72     4.70    0.55
 217 K-    -321   1 211 189   0   0   -1.43    0.96   -12.18    12.31    0.49
 218 PI+    211   1 211 189   0   0   -0.29   -0.01    -1.19     1.23    0.14
 219 PI0    111   1 211 189   0   0   -1.26    0.59   -19.48    19.53    0.13
 220 K0S    310 198 215 175 223 224   -0.10   -0.24     0.13     0.58    0.50
 221 GAMA    22   1 216 175   0   0    0.12   -0.41     0.04     0.43    0.00
 222 GAMA    22   1 216 175   0   0    0.07   -3.92     1.68     4.27    0.00
 223 PI-   -211   1 220 175   0   0    0.06   -0.08     0.24     0.29    0.14
 224 PI+    211   1 220 175   0   0   -0.16   -0.16    -0.10     0.29    0.14

                       ---SOFT UNDERLYING EVENT---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 225 SOFT     0 170  69  82 226 378   -0.04    0.07   159.29  1230.51 1220.16
 226 CLUS    91 184 225   0 227 228   -0.09    0.20   518.20   518.20    2.18
 227 DLB- -2214 197 226   0 229 230   -0.01    0.25   400.61   400.61    1.23
 228 OMEG   223 197 226   0 231 232   -0.08   -0.05   117.59   117.59    0.78
 229 PI0    111   1 227   0   0   0   -0.01   -0.18    63.93    63.93    0.13
 230 PBAR -2212   1 227   0   0   0    0.00    0.42   336.68   336.68    0.94
 231 GAMA    22   1 228   0   0   0    0.07   -0.01     0.95     0.95    0.00
 232 PI0    111   1 228   0   0   0   -0.14   -0.04   116.63   116.63    0.13
 233 CLUS    91 185 225   0 234 235   -1.14   -0.04  -277.65   277.68    3.80
 234 K**0   315 197 233   0 236 237   -1.39    0.93  -179.23   179.24    1.43
 235 SG*0  3214 197 233   0 238 239    0.25   -0.97   -98.42    98.44    1.38
 236 RHO-  -213 198 234   0 240 241   -0.84    0.58   -80.31    80.32    0.77
 237 K+     321   1 234   0   0   0   -0.55    0.35   -98.92    98.93    0.49
 238 PI-   -211   1 235   0   0   0    0.04   -0.10   -19.22    19.22    0.14
 239 SIG+  3222 198 235   0 242 243    0.21   -0.87   -79.21    79.22    1.19
 240 PI0    111   1 236   0   0   0   -0.88    0.65   -73.31    73.32    0.13
 241 PI-   -211   1 236   0   0   0    0.04   -0.07    -7.00     7.00    0.14
 242 PI+    211   1 239   0   0   0    0.16   -0.30   -26.09    26.09    0.14
 243 N     2112   1 239   0   0   0    0.05   -0.57   -53.12    53.13    0.94
 244 CLUS    91 186 225   0 245 246   -0.28   -0.14    31.76    31.81    1.71
 245 K0     311 197 244   0 247 247   -0.16    0.21     5.29     5.32    0.50
 246 K*-   -323 197 244   0 248 249   -0.11   -0.35    26.48    26.49    0.89
 247 K0S    310 198 245   0 250 251   -0.16    0.21     5.29     5.32    0.50
 248 PI-   -211   1 246   0   0   0   -0.27   -0.25    15.14    15.14    0.14
 249 KBAR  -311 198 246   0 252 252    0.16   -0.10    11.34    11.35    0.50
 250 PI-   -211   1 247   0   0   0   -0.17    0.28     2.50     2.52    0.14
 251 PI+    211   1 247   0   0   0    0.00   -0.07     2.79     2.80    0.14
 252 K0S    310 198 249   0 253 254    0.16   -0.10    11.34    11.35    0.50
 253 PI0    111   1 252   0   0   0    0.07   -0.20     3.01     3.02    0.13
 254 PI0    111   1 252   0   0   0    0.08    0.10     8.33     8.33    0.13
 255 CLUS    91 186 225   0 256 257    0.95    0.56    19.47    19.54    1.29
 256 RHO0   113 197 255   0 258 259    0.45    0.32    15.96    15.98    0.77
 257 PI0    111   1 255   0   0   0    0.50    0.24     3.51     3.56    0.13
 258 PI-   -211   1 256   0   0   0    0.37   -0.14     9.55     9.56    0.14
 259 PI+    211   1 256   0   0   0    0.08    0.46     6.41     6.43    0.14
 260 CLUS    91 186 225   0 261 262    0.06    0.60    17.26    17.33    1.54
 261 PI+    211   1 260   0   0   0    0.17    0.22     3.85     3.86    0.14
 262 A10  20113 197 260   0 263 264   -0.10    0.38    13.41    13.48    1.27
 263 PI+    211   1 262   0   0   0    0.34    0.16     3.23     3.26    0.14
 264 RHO-  -213 198 262   0 265 266   -0.45    0.22    10.18    10.22    0.77
 265 PI0    111   1 264   0   0   0    0.05   -0.20     3.56     3.56    0.13
 266 PI-   -211   1 264   0   0   0   -0.50    0.42     6.62     6.66    0.14
 267 CLUS    91 186 225   0 268 269   -0.10   -0.36    31.15    31.37    3.67
 268 F0     225 197 267   0 270 271    1.40   -0.43    19.34    19.43    1.27
 269 RHO-  -213 197 267   0 272 273   -1.50    0.08    11.81    11.93    0.77
 270 PI-   -211   1 268   0   0   0    0.92    0.07     5.45     5.53    0.14
 271 PI+    211   1 268   0   0   0    0.48   -0.50    13.89    13.90    0.14
 272 PI0    111   1 269   0   0   0   -1.14   -0.24     7.53     7.62    0.13
 273 PI-   -211   1 269   0   0   0   -0.36    0.32     4.28     4.31    0.14
 274 CLUS    91 186 225   0 275 276   -0.65    1.07    25.11    25.30    2.83
 275 K**+   325 197 274   0 277 278   -0.24    0.62    10.86    10.97    1.43
 276 QA0B-20313 197 274   0 279 280   -0.41    0.45    14.26    14.33    1.34
 277 PI+    211   1 275   0   0   0    0.31   -0.25     3.68     3.71    0.14
 278 K0     311 198 275   0 281 281   -0.55    0.86     7.17     7.26    0.50
 279 PI+    211   1 276   0   0   0   -0.42   -0.05     4.13     4.15    0.14
 280 K*-   -323 198 276   0 282 283    0.01    0.50    10.13    10.18    0.89
 281 K0S    310 198 278   0 284 285   -0.55    0.86     7.17     7.26    0.50
 282 PI0    111   1 280   0   0   0   -0.28    0.15     3.81     3.82    0.13
 283 K-    -321   1 280   0   0   0    0.29    0.36     6.32     6.36    0.49
 284 PI-   -211   1 281   0   0   0   -0.43    0.69     4.30     4.38    0.14
 285 PI+    211   1 281   0   0   0   -0.12    0.17     2.87     2.88    0.14
 286 CLUS    91 186 225   0 287 288   -0.28   -0.15    19.67    19.84    2.56
 287 PI-   -211   1 286   0   0   0   -0.85    0.51     7.72     7.79    0.14
 288 A2+    215 197 286   0 289 290    0.57   -0.66    11.95    12.05    1.32
 289 PI0    111   1 288   0   0   0    0.06   -0.62     5.94     5.97    0.13
 290 RHO+   213 198 288   0 291 292    0.50   -0.04     6.01     6.08    0.77
 291 PI0    111   1 290   0   0   0    0.53   -0.11     5.74     5.77    0.13
 292 PI+    211   1 290   0   0   0   -0.03    0.07     0.27     0.31    0.14
 293 CLUS    91 186 225   0 294 295   -0.27   -0.18     8.10     8.39    2.14
 294 OMEG   223 197 293   0 296 298    0.15    0.53     4.83     4.92    0.78
 295 OMEG   223 197 293   0 299 301   -0.41   -0.71     3.28     3.47    0.78
 296 PI0    111   1 294   0   0   0    0.13    0.27     1.97     2.00    0.13
 297 PI-   -211   1 294   0   0   0   -0.03    0.11     0.25     0.31    0.14
 298 PI+    211   1 294   0   0   0    0.04    0.15     2.60     2.61    0.14
 299 PI0    111   1 295   0   0   0   -0.08   -0.13     0.34     0.39    0.13
 300 PI-   -211   1 295   0   0   0    0.05   -0.04     0.21     0.26    0.14
 301 PI+    211   1 295   0   0   0   -0.38   -0.54     2.73     2.81    0.14
 302 CLUS    91 186 225   0 303 304    0.51   -0.45    11.34    11.85    3.37
 303 RHO-  -213 197 302   0 305 306   -0.79   -0.86     3.17     3.47    0.77
 304 A2+    215 197 302   0 307 308    1.30    0.41     8.17     8.38    1.32
 305 PI0    111   1 303   0   0   0   -0.30   -0.58     0.90     1.12    0.13
 306 PI-   -211   1 303   0   0   0   -0.49   -0.28     2.28     2.35    0.14
 307 PI0    111   1 304   0   0   0    0.29    0.50     3.36     3.41    0.13
 308 RHO+   213 198 304   0 309 310    1.01   -0.08     4.81     4.97    0.77
 309 PI0    111   1 308   0   0   0   -0.02    0.09     1.33     1.34    0.13
 310 PI+    211   1 308   0   0   0    1.03   -0.17     3.48     3.64    0.14
 311 CLUS    91 186 225   0 312 313   -1.61   -0.81     6.00     6.53    1.85
 312 K*0    313 197 311   0 314 315   -0.19   -0.51     2.56     2.77    0.89
 313 KBAR  -311 197 311   0 316 316   -1.43   -0.30     3.44     3.77    0.50
 314 PI-   -211   1 312   0   0   0   -0.30   -0.01     0.90     0.96    0.14
 315 K+     321   1 312   0   0   0    0.11   -0.50     1.66     1.81    0.49
 316 K0L    130   1 313   0   0   0   -1.43   -0.30     3.44     3.77    0.50
 317 CLUS    91 186 225   0 318 319    0.08    0.36     2.78     3.24    1.61
 318 A2-   -215 197 317   0 320 321    0.09    0.30     2.77     3.09    1.32
 319 PI0    111   1 317   0   0   0   -0.01    0.07     0.01     0.15    0.13
 320 PI-   -211   1 318   0   0   0    0.15    0.44     1.63     1.70    0.14
 321 RHO0   113 198 318   0 322 323   -0.06   -0.14     1.14     1.39    0.77
 322 PI-   -211   1 321   0   0   0    0.17   -0.08     1.07     1.10    0.14
 323 PI+    211   1 321   0   0   0   -0.24   -0.06     0.07     0.29    0.14
 324 CLUS    91 186 225   0 325 326   -0.21    0.63    -0.01     1.28    1.10
 325 PI+    211   1 324   0   0   0    0.33    0.60    -0.14     0.71    0.14
 326 PI-   -211   1 324   0   0   0   -0.53    0.03     0.13     0.57    0.14
 327 CLUS    91 186 225   0 328 329   -0.33   -1.92    -0.45     2.58    1.63
 328 RHO0   113 197 327   0 330 331    0.31   -1.51    -0.09     1.72    0.77
 329 PI+    211   1 327   0   0   0   -0.65   -0.41    -0.36     0.86    0.14
 330 PI-   -211   1 328   0   0   0    0.34   -0.85     0.27     0.96    0.14
 331 PI+    211   1 328   0   0   0   -0.02   -0.66    -0.36     0.76    0.14
 332 CLUS    91 186 225   0 333 334   -0.61   -0.72    -2.37     3.24    2.00
 333 PI-   -211   1 332   0   0   0   -1.03   -0.59    -2.49     2.76    0.14
 334 PI0    111   1 332   0   0   0    0.42   -0.13     0.12     0.48    0.13
 335 CLUS    91 186 225   0 336 337    0.69   -0.53    -4.01     4.66    2.20
 336 QA+  20323 197 335   0 338 339    0.89   -0.76    -2.90     3.40    1.34
 337 KBAR  -311 197 335   0 340 340   -0.20    0.23    -1.11     1.25    0.50
 338 PI+    211   1 336   0   0   0    0.49    0.01    -1.11     1.22    0.14
 339 K*0    313 198 336   0 341 342    0.40   -0.78    -1.80     2.19    0.89
 340 K0L    130   1 337   0   0   0   -0.20    0.23    -1.11     1.25    0.50
 341 PI-   -211   1 339   0   0   0   -0.07   -0.42    -0.46     0.64    0.14
 342 K+     321   1 339   0   0   0    0.48   -0.35    -1.34     1.55    0.49
 343 CLUS    91 186 225   0 344 345    0.15   -0.58   -14.67    14.86    2.30
 344 A2-   -215 197 343   0 346 347   -0.17   -0.61    -7.39     7.53    1.32
 345 RHO0   113 197 343   0 348 349    0.33    0.02    -7.29     7.33    0.77
 346 PI0    111   1 344   0   0   0   -0.03   -0.49    -1.36     1.45    0.13
 347 RHO-  -213 198 344   0 350 351   -0.15   -0.12    -6.03     6.08    0.77
 348 PI-   -211   1 345   0   0   0   -0.16   -0.17    -1.92     1.94    0.14
 349 PI+    211   1 345   0   0   0    0.49    0.20    -5.37     5.39    0.14
 350 PI0    111   1 347   0   0   0    0.03    0.25    -1.21     1.24    0.13
 351 PI-   -211   1 347   0   0   0   -0.17   -0.37    -4.81     4.83    0.14
 352 CLUS    91 186 225   0 353 354    1.06    0.42   -15.95    16.12    2.02
 353 K+     321   1 352   0   0   0    0.13   -0.03    -1.95     2.02    0.49
 354 QA0B-20313 197 352   0 355 356    0.92    0.45   -14.00    14.10    1.34
 355 RHO+   213 198 354   0 357 358    0.42    0.44    -8.53     8.58    0.77
 356 K-    -321   1 354   0   0   0    0.50    0.01    -5.47     5.52    0.49
 357 PI0    111   1 355   0   0   0    0.04    0.11    -5.95     5.96    0.13
 358 PI+    211   1 355   0   0   0    0.39    0.33    -2.57     2.63    0.14
 359 CLUS    91 186 225   0 360 361    0.43    0.35   -12.99    13.09    1.48
 360 ETA    221 197 359   0 362 364    0.61    0.57   -12.06    12.10    0.55
 361 PI-   -211   1 359   0   0   0   -0.19   -0.22    -0.93     0.99    0.14
 362 PI0    111   1 360   0   0   0    0.23    0.15    -5.41     5.42    0.13
 363 PI0    111   1 360   0   0   0    0.22    0.14    -2.35     2.37    0.13
 364 PI0    111   1 360   0   0   0    0.16    0.28    -4.30     4.31    0.13
 365 CLUS    91 186 225   0 366 367    1.48    0.54   -28.43    28.54    1.90
 366 RHO+   213 197 365   0 368 369    1.19   -0.21   -19.84    19.90    0.77
 367 ETA    221 197 365   0 370 372    0.30    0.75    -8.59     8.64    0.55
 368 PI0    111   1 366   0   0   0    0.22   -0.36    -6.15     6.17    0.13
 369 PI+    211   1 366   0   0   0    0.97    0.15   -13.69    13.73    0.14
 370 GAMA    22   1 367   0   0   0    0.00    0.43    -2.89     2.92    0.00
 371 PI-   -211   1 367   0   0   0    0.14    0.14    -2.99     3.00    0.14
 372 PI+    211   1 367   0   0   0    0.15    0.18    -2.70     2.72    0.14
 373 CLUS    91 186 225   0 374 375   -0.06    0.34   -39.65    39.68    1.53
 374 RHO-  -213 197 373   0 376 377    0.19   -0.32   -20.23    20.25    0.77
 375 PI0    111   1 373   0   0   0   -0.25    0.65   -19.42    19.43    0.13
 376 PI0    111   1 374   0   0   0    0.16   -0.46   -18.41    18.42    0.13
 377 PI-   -211   1 374   0   0   0    0.03    0.14    -1.82     1.83    0.14
 378 CLUS    91 186 225   0 379 380    0.17    0.89  -135.36   135.38    2.15
 379 RHO0   113 197 378   0 381 382    0.39    0.07  -113.48   113.49    0.77
 380 PI+    211   1 378   0   0   0   -0.22    0.82   -21.88    21.90    0.14
 381 PI-   -211   1 379   0   0   0   -0.15   -0.06   -14.42    14.42    0.14
 382 PI+    211   1 379   0   0   0    0.54    0.14   -99.06    99.06    0.14

         OUTPUT ON ELEMENTARY PROCESS

         NUMBER OF EVENTS   =         100
         NUMBER OF WEIGHTS  =        2640
         MEAN VALUE OF WGT  =  0.2174E+04
         RMS SPREAD IN WGT  =  0.6626E+04
         ACTUAL MAX WEIGHT  =  0.5505E+05
         ASSUMED MAX WEIGHT =  0.5639E+05

         PROCESS CODE IPROC =        1705
         CROSS SECTION (PB) =2173900.2123
         ERROR IN C-S  (PB) = 128956.9891
         EFFICIENCY PERCENT =      3.8554
FORTRAN STOP
 -----------------------------------------------------------------------

                  *****20. GUIDE TO SAMPLE OUTPUT*****

   After listing  the more important input parameter values, the program
   prints the messages

         PDFLIB STRUCT FUNCTIONS NOT USED

   indicating that the  CERN PDFLIB  structure function library will not
   be used (MODPDF<0), and

         NO EVENTS WILL BE WRITTEN TO DISK

   to remind the user that LWEVT=0 for this run. Then a table of Sudakov
   form factors  for parton branching is read from  unit 7,  having been
   computed in a previous run (LRSUD=7).

   The default particle data table is modified by calling HWUSTA('PI0 ')
   to suppress pi0 decays:

         PARTICLE TYPE  21=PI0  SET STABLE

   Next the program  searches for the  maximum weight,  i.e. the maximum
   cross section in the available phase space, as implied by the default
   value WGTMAX=0. The parameters

         MIN P-TRAN FOR 2->2    =   10.0000
         MAX P-TRAN FOR 2->2    =  900.0000
   with
         PROCESS CODE       =        1705

   mean that the transverse momentum of the b quark in the QCD 2->2 hard
   subprocesses  is required  to be  greater than  10 GeV/c.  After this
   search, the estimated total cross section of relevant subprocesses in
   this region of phase space is printed, together with the anticipated
   efficiency of subprocess generation (i.e. average/maximum weight):

         CROSS SECTION (PB) =2447328.6400
         ERROR IN C-S  (PB) = 161219.9097
         EFFICIENCY PERCENT =      4.3404

   Since the default is  MAXPR=1,  the first generated event is printed.

   The event heading

 EVENT      1:     900.00 GEV/C PBAR ON     900.00 GEV/C P     PROCESS:  1705

 SEEDS:      17673 &      63565   STATUS: 100  ERROR:   0  WEIGHT: 0.2447E+04

   tells us  the beam and target, the random number seeds at the start of
   the  event and the process code IPROC. The status 100 means a complete
   event  was generated  and the zero  error code means  no problems were
   encountered.  Since  NOWGT=.TRUE. (unweighted event generation),  each
   event has the mean weight computed earlier.

   Next come the contents of  COMMON/HEPEVT/  and related quantities.  The
   various parts of this particular event are located as follows:

             +---------+--------------------------------------+
             |   Entry | Description                          |
             +---------+--------------------------------------+
             |   1-  3 | Initial state                        |
             |   4-  8 | Hard subprocess: g+g -> b+bbar       |
             |   9- 32 | Parton showers                       |
             |  33- 68 | Gluon splitting                      |
             |  69- 90 | Cluster formation                    |
             |  91-172 | Cluster and hadron decays            |
             | 173-184 | Weak decays of B- and B0 mesons      |
             | 185-224 | Hadronization of B-/0 decay products |
             | 225-382 | Soft underlying event                |
             +---------+--------------------------------------+

   We discuss each part in turn.

                           ---INITIAL STATE---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
   1 PBAR -2212 101   0   0   0   0    0.00    0.00   900.00   900.00    0.94
   2 P     2212 102   0   0   0   0    0.00    0.00  -900.00   900.00    0.94
   3 CMF      0 103   0   0   0   0    0.00    0.00     0.00  1800.00 1800.00

   CMF represents  the overall centre of mass of  the initial state.  The
   'mother' MOi=JMOHEP(i,IHEP) and 'daughter' DAi=JDAHEP(i,IHEP) pointers
   are set to zero for these entries.

                          ---HARD SUBPROCESS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
   4 GLUE    21 121   6   7   9   5    0.00    0.00    49.00    49.00    0.75
   5 BBAR    -5 122   6   4  15   8    0.00    0.00    -5.19     7.35    5.20
   6 HARD     0 120   4   5   7   8    8.17   -5.11    43.81    57.17   35.45
   7 GLUE    21 123   6   8  21   4    5.97   11.07    40.40    42.32    0.75
   8 BBAR    -5 124   6   5  28   7   -5.97  -11.07     3.41    14.03    5.20

   In this event the subprocess is 'flavour excitation',  g+bbar->g+bbar.
   HARD is the  hard subprocess  centre of mass.  Its mother and daughter
   pointers give the locations of the incoming and outgoing partons.  The
   status codes 121-124 correspond to partons 1-4 in the hard subprocess.
   The first  mother pointers show the location of the hard c.m., and the
   second mother  of each parton  is the  'colour  mother',  as explained
   above. Thus the colours of partons 1234 are connected to 3142 respect-
   ively, corresponding to process  IHPRO=25. Similarly, the first daugh-
   ter points to the associated jet but the second daughter is the colour
   daughter, i.e. the parton to which this one's anticolour is connected.
   Thus the anticolour connections  of 1234 in this case are to 2413. The
   colour diagram is

                        (g)1 --<-------<-- 3(g)
                             -->--+ +-->--
                                  | |
                                  | |
                     (bbar)2 --<--+ +--<-- 4(bbar)

   Note that for specifying the colour connections all lines are regarded
   as outgoing, and that since antiquarks  carry no colour MO2 is in that
   case  used for the flavour connection (similarly with DA2 for quarks).
   Gluon radiation from the incoming bbar will be limited by interference
   with gluon 1,  that from the outgoing bbar by gluon 3,  gluon 1 by the
   incoming bbar or gluon 3, and gluon 3 by the outgoing bbar or gluon 1.
   The momenta and masses of the partons are the raw on-shell values gen-
   erated before QCD radiative corrections,  but HARD has been updated to
   give the true hard  subprocess momentum after initial- and final-state
   parton branching.

                          ---PARTON SHOWERS---

   The QCD cascade from each hard parton is generated in sequence. First
   there is a jet entry (IDHEP=94)  giving the total jet momentum,  mass
   and flavour. For initial-state jets the mass represents  -|q**2|**1/2
   for the virtual parton  entering the  hard subprocess.  MO1 gives the
   parent hard parton and MO2 the hard centre-of-mass. DO1 and DO2 point
   to the first and last parton in the jet after perturbative branching.
   If branching occurs, the next entry  (CONE)  is a lightlike  4-vector
   defining the  radiation  cone  and the  orientation of  the radiation
   pattern.

   The partons in the jet  (ISTHEP=157, plus 155,156 for spectators, with
   gluons  reset to 2 by  gluon splitting subroutine  HWCGSP)  have their
   colour and anticolour connections specified by MO2 and DA2 respective-
   ly, as described above for the hard subprocess. Gluon jet 1 is:

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
   9 GLUE    94 141   4   6  11  14    3.81    0.90    50.87    50.70   -5.67
  10 CONE     0 100   4   7   0   0    0.47    0.88     2.41     2.61    0.00
  11 GLUE    21   2   9  12  33  34   -1.23   -0.28    33.27    33.30    0.75
  12 GLUE    21   2   9  13  35  36   -1.81   -1.85    30.74    30.85    0.75
  13 DBAR    -1 157   9  14  84  56   -0.69    1.09    63.44    63.45    0.32
  14 UBUB -2203 155   9  49  69  13    0.00    0.00   626.16   626.16    0.64

   The incoming bbar jet must contain a b quark to conserve flavour:

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  15 BBAR    94 142   5   6  17  20    4.36   -6.01    -7.06     6.46   -7.95
  16 CONE     0 100   5   4   0   0   -0.69   -0.72     1.70     1.97    0.00
  17 BOTM     5 157  15  51  70  32   -3.10    5.14   -63.03    63.53    5.20
  18 UD    2101 156  15  19  82  52    0.00    0.00  -527.92   527.92    0.64
  19 UP       2 157  15  53  71  18    0.61   -1.83  -178.83   178.84    0.32
  20 GLUE    21   2  15  33  37  38   -1.88    2.83   -80.06    80.14    0.75

   The outgoing gluon jet contains a perturbative s-sbar pair:

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  21 GLUE    94 143   7   6  23  27    9.16    4.95    34.61    37.96   11.59
  22 CONE     0 100   7   8   0   0   -0.34   -0.79     0.70     1.11    0.00
  23 GLUE    21   2  21  24  39  40    0.97    2.06    11.95    12.19    0.75
  24 SBAR    -3 157  21  25  76  40    0.62    0.41    12.20    12.23    0.50
  25 STRA     3 157  21  41  72  24    2.76    0.90     5.42     6.17    0.50
  26 GLUE    21   2  21  27  41  42    2.21    0.79     3.08     3.94    0.75
  27 GLUE    21   2  21  30  43  44    2.58    0.80     1.97     3.43    0.75

   The outgoing bbar radiated two gluons:

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  28 BBAR    94 144   8   6  30  32   -0.99  -10.06     9.19    19.21   13.51
  29 CONE     0 100   8   7   0   0    0.22    0.90     0.51     1.05    0.00
  30 GLUE    21   2  28  31  45  46   -0.44    1.69     1.76     2.59    0.75
  31 GLUE    21   2  28  32  47  48    1.06    0.55     0.86     1.65    0.75
  32 BBAR    -5 157  28  17  80  48   -1.60  -12.30     6.57    14.97    5.20

                          ---GLUON SPLITTING---

   As the first step  in the cluster  hadronization model,  any gluons in
   the jets are split into light  quark-antiquark pairs.  The flavours of
   the pairs are  chosen at random  amongst those allowed  by kinematics.
   The colour connections are remade accordingly.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  33 DBAR    -1 158   9  34  90  68   -0.18   -0.06     4.28     4.29    0.32
  34 DOWN     1 158   9  35  73  33   -0.87   -0.16    24.76    24.78    0.32
  35 DBAR    -1 158   9  36  73  34   -0.54   -0.43     9.16     9.19    0.32
  36 DOWN     1 158   9  55  74  35   -0.93   -1.03    16.12    16.18    0.32
 .......
  47 DBAR    -1 158  28  48  79  46    0.72    0.52     0.54     1.09    0.32
  48 DOWN     1 158  28  32  80  47    0.34    0.04     0.32     0.57    0.32

   Each quark  (or antidiquark) is combined with its colour mother anti-
   quark (or diquark) to make a cluster with the sum of their 4-momenta.
   All  non-beam  clusters with  masses above  the maximum  are split by
   creating new quark-antiquark pairs with  ISTHEP=159  (8 such pairs in
   this event).  The beam remnant clusters,  i.e., those  containing the
   spectator  quarks from  the incident hadrons  (ISTHEP = 167,168)  are
   split into 2 "soft" clusters each  (see new features of  version 4.3,
   above), making another two pairs.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  49 DBAR    -1 159   9  50  69  14    0.00    0.01    68.74    68.74    0.32
  50 DOWN     1 159  21  39  81  49    0.01    0.03    19.19    19.19    0.32
  51 DBAR    -1 159  15  52  70  17   -0.04    0.06    -8.67     8.68    0.32
  52 DOWN     1 159  15  18  82  51   -0.04    0.07    -7.69     7.69    0.32
 .......
  67 UBAR    -2 159   9  68  88  64   -0.01    0.00     0.10     0.33    0.32
  68 UP       2 159   9  33  90  67   -0.11   -0.04     2.48     2.50    0.32

                         ---CLUSTER FORMATION---

   Next the clusters themselves are listed. The mothers of a cluster are
   the partons from which it is made,  and the daughters are the primary
   hadrons into which it decays.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  69 CLUS    91 167  14  49 225   0    0.00    0.00   694.90   694.90    1.22
  70 CLUS    91 183  17  51  91  92   -3.14    5.21   -71.70    72.21    5.97
  71 CLUS    91 183  19  53  93  94    0.57   -1.82  -193.38   193.39    1.38
 .......
  89 CLUS    91 183  66  63 127 128   -0.04    0.02    -0.07     1.20    1.20
  90 CLUS    91 183  68  33 129 130   -0.29   -0.10     6.75     6.79    0.66

                          ---CLUSTER DECAYS---

   The non-beam clusters,  including the  b-flavoured clusters 70 and 80,
   now decay isotropically into pairs of hadrons chosen according to den-
   sity  of  states.  Particles  with  ISTHEP=1  are  stable.  ISTHEP=199
   indicates a heavy (b or t) hadron  which will later decay weakly via a
   secondary hard subprocess.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
  91 B-    -521 199  70  15 173 174   -2.32    4.11   -63.08    63.48    5.27
  92 PI+    211   1  70  15   0   0   -0.82    1.10    -8.62     8.73    0.14
  93 PI+    211   1  71  15   0   0   -0.22   -0.71  -113.64   113.64    0.14
  94 PI0    111   1  71  15   0   0    0.79   -1.11   -79.74    79.75    0.13
 .......
 111 PI-   -211   1  80  28   0   0    0.56   -3.35     1.41     3.68    0.14
 112 B+     521 199  80  28 175 176   -1.82   -8.92     5.47    11.86    5.27
 113 PI-   -211   1  81  21   0   0    1.07    0.70     8.59     8.69    0.14
 114 OMEG   223 197  81  21 148 150   -0.51    0.60    18.59    18.63    0.78
 .......
 129 PI0    111   1  90   9   0   0   -0.43   -0.02     3.06     3.09    0.13
 130 PI+    211   1  90   9   0   0    0.14   -0.07     3.70     3.70    0.14

                       ---STRONG HADRON DECAYS---

   Next come  the decay  products of  unstable hadrons  generated  in the
   cluster decays.  Remember that the pi0 was set  stable in the initial-
   ization phase.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 131 PI-   -211   1  97   9   0   0   -0.98   -0.63    16.58    16.62    0.14
 132 PI+    211   1  97   9   0   0   -0.28    0.00    11.64    11.64    0.14
 .......
 171 PI-   -211   1 159   9   0   0    0.01    0.07    -1.95     1.96    0.14
 172 PI+    211   1 159   9   0   0   -0.14   -0.36    -0.59     0.72    0.14
                       ---HEAVY FLAVOUR DECAYS---

   The B- and B+  are split into collinear  heavy quarks  and spectators:

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 173 BOTM     5 153  91 174 177 179   -2.18    3.86   -59.25    59.62    4.95
 174 UBAR    -2 125  91 179 183 179   -0.14    0.25    -3.83     3.85    0.32
 175 UP       2 125 112 182 184 182   -0.11   -0.54     0.33     0.72    0.32
 176 BBAR    -5 153 112 175 180 182   -1.71   -8.37     5.14    11.14    4.95

   Then the heavy quarks  decay weakly  and the spectators are copied and
   given the correct colour connection labels:

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 177 UBAR    -2 123 173 178 185 178    0.46    0.82    -8.43     8.49    0.32
 178 DOWN     1 124 173 177 187 177    0.55    1.58   -16.23    16.32    0.32
 179 CHRM     4 124 173 173 189 173   -3.19    1.47   -34.60    34.82    1.80
 180 UP       2 123 176 181 191 181   -0.35   -0.50    -0.24     0.73    0.32
 181 DBAR    -1 124 176 180 193 180   -1.73   -3.45     3.62     5.30    0.32
 182 CBAR    -4 124 176 176 195 176    0.37   -4.43     1.77     5.11    1.80
 183 UBAR    -2 160 174 190 199 190   -0.14    0.25    -3.83     3.85    0.32
 184 UP       2 160 175 196 197 196   -0.11   -0.54     0.33     0.72    0.32

                ---HADRONIZATION OF B DECAY PRODUCTS---

   The heavy flavour  decays are  treated as new hard processes, in which
   secondary parton showers may be  generated.  The branching phase space
   is small and in this event none of the decay quarks emits a gluon.

                          ---PARTON SHOWERS---

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 185 UBAR    94 143 177 173 186 186    0.46    0.82    -8.43     8.49    0.32
 186 UBAR    -2 157 185 188 198 188    0.46    0.82    -8.43     8.49    0.32
 187 DOWN    94 144 178 173 188 188    0.55    1.58   -16.23    16.32    0.32
 188 DOWN     1 157 187 186 198 186    0.55    1.58   -16.23    16.32    0.32
 189 CHRM    94 144 179 173 190 190   -3.19    1.47   -34.60    34.82    1.80
 190 CHRM     4 157 189 183 199 183   -3.19    1.47   -34.60    34.82    1.80
 191 UP      94 143 180 176 192 192   -0.35   -0.50    -0.24     0.73    0.32
 192 UP       2 157 191 194 200 194   -0.35   -0.50    -0.24     0.73    0.32
 193 DBAR    94 144 181 176 194 194   -1.73   -3.45     3.62     5.30    0.32
 194 DBAR    -1 157 193 192 200 192   -1.73   -3.45     3.62     5.30    0.32
 195 CBAR    94 144 182 176 196 196    0.37   -4.43     1.77     5.11    1.80
 196 CBAR    -4 157 195 184 197 184    0.37   -4.43     1.77     5.11    1.80

                         ---CLUSTER FORMATION---

   The weak decay products are thus four clusters:

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 197 CLUS    91 183 184 196 201 202    0.26   -4.97     2.10     5.83    2.19
 198 CLUS    91 183 188 186 203 204    1.02    2.39   -24.65    24.80    0.72
 199 CLUS    91 183 190 183 205 206   -3.33    1.72   -38.43    38.68    2.26
 200 CLUS    91 183 192 194 207 208   -2.08   -3.95     3.38     6.03    2.25

                          ---CLUSTER DECAYS---

   The clusters decay as in a primary hard process.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 201 PI0    111   1 197 175   0   0    0.05   -0.25     0.22     0.36    0.13
 202 DC*B  -423 197 197 175 209 210    0.21   -4.72     1.88     5.47    2.01
 203 PI0    111   1 198 187   0   0    0.99    2.32   -23.61    23.75    0.13
 204 PI-   -211   1 198 187   0   0    0.03    0.07    -1.04     1.05    0.14
 205 DC*+   413 197 199 189 211 212   -3.27    1.70   -36.09    36.33    2.01
 206 PI-   -211   1 199 189   0   0   -0.06    0.02    -2.34     2.34    0.14
 207 N     2112   1 200 191   0   0   -0.86   -1.96     1.85     2.98    0.94
 208 DLB+ -1114 197 200 191 213 214   -1.22   -1.99     1.52     3.05    1.23

                       ---STRONG HADRON DECAYS---

   The subsequent  charmed  particle  decays are  generated  according to
   simplified particle data tables.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 209 DCBR  -421 198 202 175 215 216    0.09   -4.58     1.85     5.28    1.86
 210 GAMA    22   1 202 175   0   0    0.12   -0.14     0.03     0.19    0.00
 211 DC0    421 198 205 189 217 219   -2.97    1.54   -32.84    33.07    1.86
 212 PI+    211   1 205 189   0   0   -0.30    0.15    -3.25     3.27    0.14
 213 PI+    211   1 208 191   0   0   -0.29   -0.20     0.41     0.57    0.14
 214 NBAR -2112   1 208 191   0   0   -0.93   -1.79     1.11     2.48    0.94
 215 K0     311 198 209 175 220 220   -0.10   -0.24     0.13     0.58    0.50
 216 ETA    221 198 209 175 221 222    0.20   -4.34     1.72     4.70    0.55
 217 K-    -321   1 211 189   0   0   -1.43    0.96   -12.18    12.31    0.49
 218 PI+    211   1 211 189   0   0   -0.29   -0.01    -1.19     1.23    0.14
 219 PI0    111   1 211 189   0   0   -1.26    0.59   -19.48    19.53    0.13
 .......
 223 PI-   -211   1 220 175   0   0    0.06   -0.08     0.24     0.29    0.14
 224 PI+    211   1 220 175   0   0   -0.16   -0.16    -0.10     0.29    0.14

                       ---SOFT UNDERLYING EVENT---

   The undecayed beam clusters  (69 and 82)  undergo a  soft collision at
   a c.m. energy of 1220 GeV in parallel with the hard subprocesses. This
   produces 22  soft clusters  with a flat  rapidity distribution and low
   transverse momenta,  which decay to provide the  low-pt hadrons of the
   soft underlying event. The two leading clusters appear first, then the
   ones at intermediate rapidities.

 IHEP ID  IDPDG IST MO1 MO2 DA1 DA2    P-X     P-Y      P-Z    ENERGY    MASS
 225 SOFT     0 170  69  82 226 378   -0.04    0.07   159.29  1230.51 1220.16
 226 CLUS    91 184 225   0 227 228   -0.09    0.20   518.20   518.20    2.18
 227 DLB- -2214 197 226   0 229 230   -0.01    0.25   400.61   400.61    1.23
 228 OMEG   223 197 226   0 231 232   -0.08   -0.05   117.59   117.59    0.78
 229 PI0    111   1 227   0   0   0   -0.01   -0.18    63.93    63.93    0.13
 230 PBAR -2212   1 227   0   0   0    0.00    0.42   336.68   336.68    0.94
 231 GAMA    22   1 228   0   0   0    0.07   -0.01     0.95     0.95    0.00
 232 PI0    111   1 228   0   0   0   -0.14   -0.04   116.63   116.63    0.13
 233 CLUS    91 185 225   0 234 235   -1.14   -0.04  -277.65   277.68    3.80
 234 K**0   315 197 233   0 236 237   -1.39    0.93  -179.23   179.24    1.43
 235 SG*0  3214 197 233   0 238 239    0.25   -0.97   -98.42    98.44    1.38
 236 RHO-  -213 198 234   0 240 241   -0.84    0.58   -80.31    80.32    0.77
 237 K+     321   1 234   0   0   0   -0.55    0.35   -98.92    98.93    0.49
 238 PI-   -211   1 235   0   0   0    0.04   -0.10   -19.22    19.22    0.14
 239 SIG+  3222 198 235   0 242 243    0.21   -0.87   -79.21    79.22    1.19
 240 PI0    111   1 236   0   0   0   -0.88    0.65   -73.31    73.32    0.13
 241 PI-   -211   1 236   0   0   0    0.04   -0.07    -7.00     7.00    0.14
 242 PI+    211   1 239   0   0   0    0.16   -0.30   -26.09    26.09    0.14
 243 N     2112   1 239   0   0   0    0.05   -0.57   -53.12    53.13    0.94
 .......
 378 CLUS    91 186 225   0 379 380    0.17    0.89  -135.36   135.38    2.15
 379 RHO0   113 197 378   0 381 382    0.39    0.07  -113.48   113.49    0.77
 380 PI+    211   1 378   0   0   0   -0.22    0.82   -21.88    21.90    0.14
 381 PI-   -211   1 379   0   0   0   -0.15   -0.06   -14.42    14.42    0.14
 382 PI+    211   1 379   0   0   0    0.54    0.14   -99.06    99.06    0.14

   After the 100 events requested have been generated, an analysis of the
   associated weight distribution and cross section is printed.
 -----------------------------------------------------------------------

                 ***21. SUBROUTINE DESCRIPTIONS***

       +--------+---------------------------------------------+
       |  Name  | Description                                 |
       +--------+---------------------------------------------+
       | HWIGPR | Main program                                |
       | HWIGIN | Default initializations                     |
       +--------+---------------------------------------------+
       | HWABEG | Initializes user's analysis                 |
       | HWAEND | Terminates user's analysis                  |
       | HWANAL | Performs user's analysis on event           |
       +--------+---------------------------------------------+
       | HWBAZF | Computes azimuthal correlation functions    |
       | HWBCON | Makes colour connections between jets       |
       | HWBDED | Correction to the `dead zone' in e+e-       |
       | HWBDIS | Correction to the `dead zone' in DIS        |
       | HWBFIN | Transfers external lines of jet to /HEPEVT/ |
       | HWBGEN | Finds unevolved partons and generates jets  |
       | HWBJCO | Combines jets with correct kinematics       |
       | HWBMAS | Computes masses and trans. momenta in jet   |
       | HWBRAN | Generates a timelike parton branching       |
       | HWBSPA | Computes momenta in spacelike jet           |
       | HWBSPN | Computes spin density/decay matrices        |
       | HWBSU1 | First  term in quark Sudakov form factor    |
       | HWBSU2 | Second term in quark Sudakov form factor    |
       | HWBSUD | Computes (or reads) Sudakov form factors    |
       | HWBSUG | Integrand in gluon Sudakov form factor      |
       | HWBSUL | Logarithmic part of Sudakov form factor     |
       | HWBTIM | Computes momenta in timelike jet            |
       | HWBVMC | Virtual mass cutoff for parton type ID      |
       +--------+---------------------------------------------+
       | HWCCUT | Cuts a massive cluster in two               |
       | HWCDEC | Decays clusters into primary hadrons        |
       | HWCFLA | Sets up flavours for HWCHAD                 |
       | HWCFOR | Forms clusters                              |
       | HWCGSP | Splits gluons                               |
       | HWCHAD | Decays a cluster into one or two hadrons    |
       +--------+---------------------------------------------+
       | HWDBOS | Finds and decays W and Z bosons             |
       | HWDBOZ | Chooses decay mode of W and Z bosons        |
       | HWDCLE | Interface to CLEO package for B decays      |
       | HWDEUR | Interface to EURODEC package for B decays   |
       | HWDHAD | Generates decays of unstable hadrons        |
       | HWDHGC | Higgs -> gamma gamma decay                  |
       | HWDHGF | Higgs -> W+ W- decay                        |
       | HWDHIG | Finds and decays Higgs bosons               |
       | HWDHQK | Finds and decays heavy quarks               |
       | HWDHVY | Finds and decays heavy flavour hadrons      |
       | HWDIDP | Chooses a parton for HWDHVY                 |
       | HWDPWT | Phase space decay weight                    |
       | HWDTHR | Generates a three-body decay                |
       | HWDTOP | Decides whether to decay top quark          |
       | HWDTWO | Generates a two-body decay                  |
       | HWDWWT | Weak (V-A)  decay weight                    |
       +--------+---------------------------------------------+
       | HWEFIN | Final calculations on elementary subprocess |
       | HWEGAM | Generates Weizsacker-Williams photon        |
       | HWEINI | Initializes elementary subprocess           |
       | HWEONE | Sets up a 2->1 hard subprocess              |
       | HWEPRO | Generates elementary subprocess             |
       | HWETWO | Sets up a 2->2 hard subprocess              |
       +--------+---------------------------------------------+
       | HWHBGF | Hard subprocess: boson-gluon fusion (BGF)   |
       | HWHBKI | Computes kinematics for BGF                 |
       | HWHBRN | Returns a phase-space point for BGF         |
       | HWHBSG | Computes cross section for BGF              |
       | HWHDIS | Hard subprocess: deep inelastic lepton quark|
       | HWHDYP | Hard subprocess: Drell-Yan Z0/photon prodn  |
       | HWHEGG | Hard subprocess: two-photon processes in ee |
       | HWHEGW | Hard subprocess: photon-W processes in e+e- |
       | HWHEGX | Calculates cross-section for HWHEGW         |
       | HWHEPA | Hard subprocess: e+e- -> f fbar             |
       | HWHEPG | Hard subprocess: e+e- -> q qbar gluon       |
       | HWHEW0 | e+e- -> W W / Z Z subroutine                |
       | HWHEW1 | e+e- -> W W / Z Z subroutine                |
       | HWHEW2 | e+e- -> W W / Z Z subroutine                |
       | HWHEW3 | e+e- -> W W subroutine                      |
       | HWHEW4 | e+e- -> W W / Z Z subroutine                |
       | HWHEW5 | e+e- -> Z Z subroutine                      |
       | HWHEWW | Hard subprocess: e+e- -> W W / Z Z          |
       | HWHHVY | Hard subprocess: heavy quark production     |
       | HWHIG1 | Matrix elements for Higgs + jet production  |
       | HWHIGA | Amplitudes squared for Higgs + jet          |
       | HWHIGB | Loop integrals for Higgs + jet              |
       | HWHIGJ | QCD Higgs + jet production                  |
       | HWHIGM | Choose Higgs mass for production routines   |
       | HWHIGS | Hard subprocess: gg/qqbar -> Higgs          |
       | HWHIGT | Computes gg -> Higgs cross section          |
       | HWHIGW | Hard subprocess: WW / ZZ -> Higgs           |
       | HWHIGY | Computes ee -> Z -> ZH cross section        |
       | HWHIGZ | Hard subprocess: ee -> Z -> ZH              |
       | HWHPH2 | Hard subprocess: direct photon pairs        |
       | HWHPHO | Hard subprocess: direct photon production   |
       | HWHPPB | Box contribution to gg->photon photon       |
       | HWHPPE | Pointlike photon-parton (fixed flavour)     |
       | HWHPPH | Pointlike photon-parton (fixed pair flavour)|
       | HWHPPM | Pointlike photon-parton direct light meson  |
       | HWHPPT | Pointlike photon-parton (all flavours)      |
       | HWHQCD | Hard subprocess: QCD 2->2                   |
       | HWHQCP | Identifies QCD 2->2 hard subprocess         |
       | HWHW1J | Hard subprocess: W + jet production         |
       | HWHWEX | Top production by W exchange                |
       | HWHWPR | Hard subprocess: W production               |
       +--------+---------------------------------------------+
       | HWMEVT | Generates min bias or soft underlying event |
       | HWMLPS | Generates longitudinal phase space          |
       | HWMNBI | Computes negative binomial probability      |
       | HWMULT | Chooses min bias charged multiplicity       |
       | HWMWGT | Calculates weight for minimum bias events   |
       +--------+---------------------------------------------+
       | HWRAZM | Randomly rotated azimuth                    |
       | HWREXP | Random number: exponential distribution     |
       | HWREXQ | Random number: exp. dist. with cutoff       |
       | HWREXT | Random number: exponential transverse mass  |
       | HWRGAU | Random number: Gaussian                     |
       | HWRGEN | Random number generator (l'Ecuyer method)   |
       | HWRINT | Random integer                              |
       | HWRLOG | Random logical                              |
       | HWRPOW | Random number: power distribution           |
       | HWRUNG | Random number: uniform + Gaussian tails     |
       | HWRUNI | Random number: uniform                      |
       +--------+---------------------------------------------+
       | HWSBRN | Generates spacelike parton branching        |
       | HWSDGG | Drees-Grassie photon str. function (gluon)  |
       | HWSDGQ | Drees-Grassie photon str. function (quarks) |
       | HWSFBR | Chooses a spacelike branching               |
       | HWSFUN | Hadron structure functions                  |
       | HWSGAM | Gamma function (for structure functions)    |
       | HWSGEN | Generates x values for spacelike partons    |
       | HWSGQQ | Inserts g->q qbar part of gluon form factor |
       | HWSSPC | Replaces spacelike partons by spectators    |
       | HWSSUD | Sudakov form factor/structure function      |
       | HWSTAB | Interpolates in function table (for HWSSUD) |
       | HWSVAL | Checks for valence parton                   |
       +--------+---------------------------------------------+
       | HWUAEM | Running electromagnetic coupling constant   |
       | HWUAER | Real part of photon self-energy             |
       | HWUALF | Two-loop QCD running coupling constant      |
       | HWUBPR | Prints branching data for last parton shower|
       | HWUBST | Boost event record to/from hadron-hadron cmf|
       | HWUCFF | Coefficients for e+e- and DIS cross-sections|
       | HWUCI2 | Logarithmic integral Ci_2                   |
       | HWUDAT | Block data: particle properties             |
       | HWUECM | Centre-of-mass energy                       |
       | HWUEDT | Insert or delete entries in the event record|
       | HWUEEC | Computes coefficients for e+e- cross section|
       | HWUEPR | Prints event data                           |
       | HWUEMV | Moves entries within the event record       |
       | HWUFNE | Finishes an event                           |
       | HWUGAU | Adaptive Gaussian integration               |
       | HWUIDT | Translates particle identity codes          |
       | HWUINC | Initial parameter-dependent calculations    |
       | HWUINE | Initializes an event                        |
       | HWULDO | Lorentz 4-vector dot product                |
       | HWULI2 | Logarithmic integral Li_2 (Spence function) |
       | HWULOB | Lorentz transformation: rest frame -> lab   |
       | HWULOF | Lorentz transformation: lab -> rest frame   |
       | HWULOR | Multiplies by Lorentz matrix                |
       | HWUMAS | Puts mass in 5th component of vector        |
       | HWUPCM | Centre-of-mass momentum                     |
       | HWURAP | Rapidity                                    |
       | HWURES | Computes/prints resonance data              |
       | HWUROB | Rotation by inverse of matrix R             |
       | HWUROF | Rotation by matrix R                        |
       | HWUROT | Computes rotation R from vector to z-axis   |
       | HWUSOR | Sorts an array in ascending order           |
       | HWUSQR | Square root with sign retention             |
       | HWUSTA | Makes a particle type stable                |
       | HWUTAB | Interpolates in a table                     |
       | HWUTIM | Checks time remaining (N.B. VAX Fortran)    |
       +--------+---------------------------------------------+
       | HWVDIF | Vector difference                           |
       | HWVDOT | Vector dot product                          |
       | HWVEQU | Vector equality                             |
       | HWVSCA | Vector times scalar                         |
       | HWVSUM | Vector sum                                  |
       | HWVZRO | Vector zero                                 |
       +--------+---------------------------------------------+
       | HWWARN | Issues warnings and deals with errors       |
       +--------+---------------------------------------------+