# Presentation: 656267

## To discuss the Standard Candle Processes at the Tevatron

- Exclusive Diffractive Higgs production and Related Processes
-          (the key selling points for forward proton tagging at the LHC)

- To discuss the Standard Candle Processes at the Tevatron
-  for the theoretical prediction

- 6 May 2005

## ☺      YES->  Forward Proton Tagging

- CMS &ATLAS were designed and optimised to look* beyond*
*   **the SM**  *
*** **High -pt signatures in the central region*
*         *But...                           ‘incomplete’
-  Main physics ‘**goes Forward**’
- Difficult background conditions.
-  The precision measurements are limited by systematics
- (luminosity goal of  δL ≤5%)
****  **Lack of** :
- Threshold scanning* *
-                                                                ILC chartered territory
- Quantum number analysing
- Handle on CP-violating effects in the Higgs sector
- Photon – photon reactions

**Is there a way out?**
**☺**     ** ****YES**-> ** F**orward **P**roton** T**agging
-  Rapidity Gaps     Hadron Free Zones
- Δ Mx ~ δM (Missing Mass)

**RG**

**RG**

**X**

- p

- p

- p

- p

- p

- M. Albrow,  A.Rostovtsev -00

##   PLAN

- 1.   **Introduction**
-    (a gluonic Aladdin’s lamp)
**2****.****Basic**** ****elements of Durham approach**
- (a qualitative guide)
- 3. **Prospects for ****CED ****Higgs production**.
-  the SM case
-  MSSM Higgses in the *troublesome* regions
-  MSSM with CP-violation
***Exotics***
**5.  ****Experimental  checks**
**6. Conclusion**
- 6. Ten commandments of Physics with
- Forward Protons at the LHC
-  .

##  Would provide a unique  additional tool  tc complement the conventional strategies at the LHC and ILC.

-                        (rich Old and New Physics menu)
- Higgs Hunting  (the LHC ‘core business’)       K(KMR)S- 97-04
- Photon-Photon, Photon - Hadron Physics
-  J.Ohnemus ,T.Walsh , P.Zerwas-93 ,KMR-02,  K.Piotrzkowski
-  ‘Threshold Scan’: ‘Light’  SUSY , tt...      KMR-02
- Various aspects of Diffractive Physics (soft & hard ). KMR-01
- (strong interest from cosmic rays people )
- Luminometry             KMOR-01  , K.Piotrzkowski
- High intensity Gluon Factory.  KMR-00, KMR-01
- QCD test reactions,  dijet luminosity monitor
- Searches for new heavy gluophilic states             KMR-02
-                                   **FPT**
-  Would provide a unique  additional tool  tc complement the conventional strategies at the LHC and ILC.
*                                             *
-      Higgs is only a part of a broad diffractive program@LHC

**FPT  ******** ****an additional**** ****physics menu in**** ILC@LHC**

## The basic ingredients of the KMR approach                             (1997-2005) 

- The basic ingredients of the KMR approach**            **                 (1997-2005)
-  Interplay between the soft and hard  dynamics

-                 Bialas-Landshoff-91     rescattering/absorptive
-                              ( Born -level )                       effects
- Main requirements:
- inelastically scattered protons remain intact
- active gluons do not radiate in the course of evolution up to the scale M
- <Qt> >>/\QCD     in order to go by pQCD book

- Sudakov
- suppression

- (A. Berera & J.Collins-96 )

******(CDPE) ~ 10  ***** ********(incl)**

**-4**

## (CDPE) ~  10  * incl

- (CDPE) ~  10  * incl

**-4**

- How would you explain it to your (grand) children ?

## W = S2 T2

- Forcing two (inflatable) camels to go through the eye
- of a needle

- High price to pay for such a clean  environment:
- σ (CEDP) ~ 10

- -4

-   σ( inclus.)

- Rapidity Gaps should survive hostile hadronic radiation
- damages and  ‘partonic pile-up ‘

**W = S****2 T2**

- Colour charges of the ‘digluon dipole’ are screened
- only at rd ≥  1/ (Qt)ch
- GAP   Keepers  (Survival Factors)  ,  protecting RG   against:
- the debris of QCD radiation with 1/Qt≥ ≥  1/M          **(T)**
- soft rescattering effects (necessitated by unitariy)       **(S)**

**H**

**P**

**P**

## <Qt>SP~M/2exp(-1/αs),   αs =Nc/π αs Cγ

- skewed unintegrated structure functions (suPDF)

- schematically

- (Rg=1.2 at LHC)

- T(Qt,μ)    is the probability that a gluon Qt remains untouched in the evolution up to the hard scale M/2

- T + anom .dim. → IR filter
- ( the** **apparent divergency in the Qt integration nullifies)

- <Qt>SP~M/2exp(-**1/****α****s**),   **α****s** =Nc/π αs Cγ

- SM Higgs,   <Qt>SP   ≈ 2 GeV>> ΛQCD

- (x’~Qt/√s) <<(x~ M/√s)  <<1

- An important role of subleading  terms in fg(x,x’,Qt2,μ2),
-                                                                   (SL –accuracy).
- Cross sections σ~  (fg )              ( PDF-democracy)
-    S2 KMR=0.026 (± 50%)                         SM Higgs at LHC
- (detailed two-channel eikonal analysis of soft pp data)
**surprisingly ****good**  agreement with other ‘unitarizer’s  approaches and MCs.
- S2/b2  - quite stable  (within 10-15%)
**S2****~   s**                                           (Tevatron-LHC range)
- dL/d(logM2 )  ~ 1/ (16+ M)
-     a  drastic role of Sudakov suppression (~ 1/M3)
-  σH ~** 1/M****3**   ,    (σB) ch ~ Δ M/ M

- 4

- -**016**

- 3.3

- 6

-  Jz=0 ,even P- selection rule for σ is justified
- only if    <pt>2 /<Qt>2  « 1

- ^

- ^

- ^

- ^

- (J. Pumplin-95)

## αs2/8

- pp

-                **‘****New**** **** **** ****Heavy’**** **** States****  M**

- (S2)γγ  =0.86 (KMR-02)

- αs2/8

-                  we should not underestimate   photon  fusion  !  .

-    **T****2**

-   2

**Q****C****D**-’radiation damages’

##        difficult or even impossible to explore the light Higgs CP at the LHC conventionally. 

- Prospects for high accuracy mass measurements
-  ( ΓH and even lineshape in some MSSM scenarios)
- mass window   M = 3   ~ 1 GeV (the wishlist)
-                                     ~4 GeV(currently feasible)
- Valuable quantum number filter/analyzer.
- ( 0++ dominance ;C , P-even)
-        difficult or even impossible to explore the light Higgs CP at the LHC conventionally.
- (an important ingredient of  pQCD approach,
- otherwise, large |Jz|=2 ...effects,    ~(pt/Qt)2   !)
- H ->bb ‘readily’ available
-    (gg)CED ****  bb   LO        (NLO,NNLO)** ****BG’s** -> studied
-    SM Higgs          S/B~3(1GeV/M)
- complimentary information  to the conventional studies( also  ՇՇ)
**H **→**WW*****/****WW****  - an added value**
- especially for SM Higgs with M≥ 135GeV, MSSM at l ow tanβ
-  New leverage –proton momentum correlations
-    (probes of QCD dynamics, pseudoscalar ID,
-     CP violation effects)  KMR-02

- (Helsinki group)

## ☻Experimental Advantages
Measure the Higgs mass via the missing mass technique
    Mass measurements do not involve Higgs decay products

         Experimental Challenges
Tagging the leading protons
Selection of exclusive events & backgrounds
Triggering at L1 in the LHC experiments

Model dependence of predictions:
   (soft hadronic physics is involved after all)
 resolve some/many  of the issues with Tevatron data

- Measure the Higgs mass via the missing mass technique
-     Mass measurements do not involve Higgs decay products
-          Experimental Challenges
- Tagging the leading protons
- Selection of exclusive events & backgrounds
- Triggering at L1 in the LHC experiments
- Model dependence of predictions:
-    (soft hadronic physics is involved after all)
-  resolve some/many  of the issues with Tevatron data

- There is a lot to learn from present
-  and future Tevatron diffractive data

## SM Higgs : detection is in principle guaranteed   ☺

-                  search  prospects
- (e.g, A.Djouadi, Vienna-04; G.Weiglein, CMS, 04; A.Nikitenko,UK F-m,04))
- SM Higgs : detection is in principle guaranteed   ☺
- for any mass.
- In the MSSM  h-boson most probably cannot     ☺
- escape detection ,and  in large areas
- of parameter space other Higgses can be found.
- But there are still  troublesome areas of the     ** ******
- parameter space:
-       intense coupling  regime,
-       MSSM with CP-violation.....
- More surprises may arise in other SUSY
- non-minimal extensions
-  After discovery stage (Higgs identification):
- The ambitious program of precise measurements of the mass, width, couplings,
- and, especially  of the quantum numbers and
- CP  properties would  require an interplay
- with a *ILC*

## SM Higgs Cross Section * BR

- Cross sections ~O(fb)
- Diffractive Higgs   mainly   studied for Hbb
**-****K(KMR)97-04**
**-DKMOR-02**
- Boonekamp et al. ,01-04   SM Higgs
- Petrov et al. ,04
-  Recently study extended
- for the decay into WW*,WW
- can reach higher masses
- ‘Leptonic trigger cocktail’
- (WW,bb,ZZ,)
-  **FT420**** **UK team

- Note, Hbb (120 GeV) at Tevatron  0.13 fb

## H          

- H

- b jets : 	MH = 120 GeV s = 2 fb (uncertainty factor ~2.5)
- 	MH = 140 GeV s = 0.7 fb
- MH = 120 GeV : 11 signal / O(10) background
- in 30 fb-1

- WW* : 	MH = 120 GeV s = 0.4 fb
- 	MH = 140 GeV s = 1 fb
- MH = 140 GeV : 8 signal / O(3) background in 30 fb-1

- The b jet channel is possible, with a good understanding of detectors and clever level 1 trigger (needs trigger from the central detector at Level-1)
- The WW* (, ZZ*...) channel is extremely promising : no trigger problems, better mass resolution at higher masses (even in leptonic / semi-leptonic channel), weaker dependence on jet finding algorithms
- If we see SM-like Higgs + p- tags  the quantum numbers are 0++

- Exclusive SM Higgs production

- (with detector cuts)

- (with detector cuts)

- H

## ☺ An added  value of the WW channel

- 1. ‘less demanding’ experimentally
- (trigger and mass  resolution  requirements..)
- allows to avoid the potentially difficult issue of triggering
- on the b-jets
- 2. higher acceptances and efficiencies
- 3. an extension of well elaborated conventional program,
- (existing experience, MC’s...)
- 4. the decrease in the cross section is compensated for
- by the increasing  Br and increased detection efficiency
- 5. missing  mass resolution  improves  as MH increases
- 6. the mass measurement is independent of the decay products of the central system
- 7. Better quantitative understanding of backgrounds.
- Very low backgrounds at high mass.
-  8. 0+  assignment and spin-parity analyzing power
- -  still hold
-  ☻ we should not ignore MSSM with low tan β

## Preliminary

**           ****The Benchmark process : SM Higgs production**** **

- B.C., A. De Roeck, V. A. Khoze,
- ,W. J. Stirling et. al. To be published

- B. Cox, DIS-05

## The MSSM and more exotic scenarios

- If the coupling of the Higgs-like object to gluons is large, double proton tagging becomes very attractive

-  The intense coupling regime of the MSSM
- (E.Boos et al, 02-03)
-  CP-violating MSSM Higgs physics (A.Pilaftsis,98; M.Carena et al.,00-03, B.Cox et al 03,  KMR-03, J. Ellis et al -05)
- Potentially  of great importance for electroweak baryogenesis
-  an ‘Invisible’ Higgs    (BKMR-04)

## in the same time – especially advantageous for CEDP:  ☺

-  M**A**** **≤ 120-150GeV, tan β >>1   ( E.Boos et al,02-03)
**h,H,A**- light,  practically degenerate
- large **Γ**, must be accounted for
-  the ‘standard’ modes WW*,ZZ*, γγ ...-strongly    suppressed v.s. **SM**
-  maybe the best bet – μμ -channel,
- in the same time – especially advantageous for CEDP:  **☺**
-                                                                  (KKMR 03-04)
-  σ(gg ->Higgs)Br(Higgs->bb) - significantly exceeds SM.
-   thus ,much larger  rates.
-    Γh/H ~ ΔM,
**0-**** ** is filtered out, and the h/H separation may
-   be possible
- (b) The intermediate regime: MA ≤ 500 GeV,
- tan β  <    5-10
-         (the LHC wedge, windows)
- (c) The decoupling  regime
-         MA>> 2MZ            (in reality,  MA>140 GeV, tan β>10)
-      ** ****h** is SM-like, **H/A** -heavy and approximately degenerate,
-       CEDP may  allow to filter** ****A** out

- ~

## The MSSM can be very proton tagging friendly 

- The intense coupling regime is where the masses of the 3 neutral Higgs bosons are close to each other and tan  is large

- 0++ selection rule suppresses A production:
- CEDP ‘filters out’ pseudoscalar production, leaving pure H sample for study

- MA = 130 GeV, tan = 50
- Mh = 124 GeV :71signal / (3-9) background  in 30 fb-1
- MH = 135 GeV : 124 signal / (2-6) background  in 30 fb-1
- MA = 130 GeV : 3 signal / (2-6) background  in 30 fb-1

- Well known difficult region for conventional channels, tagged proton channel may well be the discovery channel, and is certainly a powerful spin/parity filter

- The MSSM can be very proton tagging friendly

-  for 5 ϭ           BR(bb) > 0.7fb (2.7fb)  for  300 (30fb*-1*)

## with CEDP:

**with CEDP**:
**h,H** may  be
- clearly    distinguishable
- outside130+-5
-  GeV  range,
**h,H** widths are quite different

## Helping to cover the LHC gap? 

- With CEDP the mass range up to 160-170 GeV can be covered at medium tan and up to 250 GeV for very high tan ,  with 300 fb**-1**

- Helping to cover the LHC gap?

- Needs ,however, still full simulation

- needs update

## Spin Parity Analysis

- Azimuthal angle between the leaprotons depends on spin of H
- Measure the azimuthal angle of the proton on the proton taggers

- Azimuthal angle between the leading protons depends on spin of H

-  angle between protons

-  angle between protons with
- rescattering effects included

- KKMR -03

## Azimuthal asymmetry in tagged protons provides direct evidence for CP violation in Higgs sector

- CP even

- CP odd active at non-zero t

**Probing CP violation in the Higgs Sector**

- ‘CPX’ scenario (in fb)

- KMR-04

- A is practically  uPDF - independent

## Slide 25

## In the tri-mixing scenario  we expect ϭ bb ~ 1fb and proton asymmetries A ~0.1-03 

- In the** **tri-mixing scenario  we expect ϭ bb ~ 1fb and proton asymmetries A ~0.1-03

- tan β=50,  MH+=150 GeV** **

- CP- violating MSSM with large tri-mixing
**                                         **J.Ellis et al 05

## Summary of CEDP

-  The missing mass method may provide unrivalled Higgs mass resolution
*Real **discovery potential* in some scenarios
-  Very clean environment in which to identify the Higgs,for example, in the CPX  or tri-mixing scenarios
-  Azimuthal asymmetries may allow direct  measurement of CP violation in Higgs sector
-  Assuming CP conservation, any object seen with 2 tagged protons has positive C parity, is (most probably) 0+, and is a colour singlet

- e.g.  mA = 130 GeV,  tan  = 50
- (difficult for conventional detection,
- but exclusive diffractive favourable)
- L = 30 fb-1
-                                   S      B
- mh = 124.4  GeV      71      3  events
- mH = 135.5  GeV    124      2
- mA = 130     GeV        1      2

-   WW*/WW modes are looking extremely attractive.

## ...the LHC as a ‘gluino factory’   , N. Arkani-Hamed ( Pheno-05)

- ...the LHC as a ‘gluino factory’   , N. Arkani-Hamed ( Pheno-05)

- BFK-92

- KMR-02

- pp  pp + ‘nothing’                   (215 m  ?)

## low luminosity : L= 10 32 -10 33 cm -2 sec-1     (pile-up problem) ,

-   M.Albrow  & A .Rostovtsev  -00

- several extensions of the SM: a fourth generation,
-                                                         some SUSY scenarios,
-                                                         large extra dimensions
- (one of the ‘LHC headaches’ )
- the advantages of the CEDP – a sharp peak in the MM spectrum, mass determination, quantum numbers
**strong  requirements** :
-  triggering directly on L1 on the proton taggers
- low luminosity : L= 10 32 -10 33 cm -2 sec-1     (pile-up problem) ,
-  forward calorimeter  (...ZDC)                            (QED radiation , soft DDD),
-  veto from the T1, T2- type detectors      (background reduction, improving the trigger budget)

***  **various potential problems of the **FPT** approach reveals themselves*
*** **however there is a (good) chance to observe such an invisible object,*
*Which, otherwise, may have to await a **ILC*

-  searches for extra dimension – diphoton production (KMR-02)

- Up to now the diffractive production data are consistent with K(KMR)S results
- Still more work to be done to constrain
- the uncertainties
- Very low  rate of CED high-Et dijets ,observed yield
- of Central Inelastic dijets.
- (CDF, Run I, Run II)                       data up to (Et)min>50 GeV
-  ‘Factorization breaking’ between the effective diffractive structure functions measured
- at the Tevatron and HERA.
- (KKMR-01 ,a quantitative description of the results,
- both in normalization and the shape of the
- distribution)
- The ratio of high Et dijets  in production with one
- and two rapidity gaps
-  Preliminary CDF results on exclusive charmonium
- CEDP. Higher statistics is underway.
- Energy dependence of the RG survival (D0, CDF)
-  CDP of γγ, data are underway
- KKMR ...... has still survived the exclusion limits
- set by the Tevatron data.... (M.Gallinaro, hep-ph/01410232)

## Tevatron  vs HERA:Factorization Breakdown

**(K.G0ulianos, PLB 358 (1995) 379)**

**p**

- well

##  rejection  of  ‘optimistic’ 

- Exclusive Dijets in Run I

- KMR-00

- )

-  e+e- -> jj
- with similar jet selection

**** rejection  of  ‘optimistic’
- theoretical  models

## Exclusive Dijet production from CDF2LHC 

- Exclusive Dijet production from CDF2LHC

- M. Gallinero (hep-ph/0504025)

- ~1 nb, KMR-00

- ~40pb, KMRS-04

- KMR model,   ‘at the time of writing  has still survived the exclusive limits set by the Tevatron data ‘

- M. Gallinero (hep-ph/0504025)

##   We are in the’ Higgs range’

- (M.Gallinaro, 04.02.2005)

- (KMRS  ~ 1pb)

- KMR expectation : ϭjj(CEDP) ~ 1/ (ET min )

- 5.3

- Limits on exclusive production

- KMRS

-   We are in the’ Higgs range’

## Preliminary

**Exclusive dijets at Tevatron**

- ExHuME Monte Carlo - direct implementation of KMR
- _[www.exhume-me.com](http://www.exhume-me.com/)_
- J. Monk and A. Pilkington, hep-ph/0502077

- Plot from B.C. and A. Pilkington, to be published

- B. Cox, DIS-05

- gg(Jz=0) qqg ,ggg       KRS
- will be implenented in ExHume MC

## CDF

- K.Goulianos, DIS-05

- Dijet production with 1&2 RGs

## KKMR-03

##    47pb

-    47pb

## C,b

- C,b

## Slide 40

## KMRS

**pp ******** p + ****γγ**** + p**

- KMRS-04

## events should be separated

## CONCLUSION

- Forward Proton Tagging would significantly extend the physics reach of the ATLAS
- and CMS detectors by giving access to a wide
- range of exciting new physics channels.
- For certain BSM scenarios the FPT may be the Higgs  discovery channel within the first
- three years of low luminosity running
-  FPT may provide a sensitive window into
- CP-violation and new physics
-    Nothing would happen  unless the  experimentalists come FORWARD and do the REAL WORK

-             We must work hard here – there is no easy solution

## of Forward Proton Tagging

**of Forward Proton Tagging**

**1. ****Thou** **shalt  not** worship any other god but the **First Principles**,
- and even if** thou** likest it not, go by thy  **Book**.
- 2. Thou slalt not make unto thee any graven image,
- thou shalt not bow down thyself  to them .   {non-perturbative  Pomeron
-                                                                                                     and its MC implementations }
- 3.Thou shalt  treat the existing diffractive experimental
-  data in ways that show great  consideration and respect. {HERA, CDF, D0}
- 4.   Thou shalt   draw thy daily guidance from the standard
- candle processes for testing thy theoretical models.
- 5. Thou shalt remember the speed of light to keep it holy.
-                                                                            (trigger latency)
- 6.Thou shalt not dishonour backgrounds and shalt study
-  them with great care.
- 7.Thou shalt not forget about the pile-up (an invention of **Satan**).
- 8. Though shalt not exceed the trigger threshold and
- the L1 saturation limit. Otherwise thy god shall
- surely punish thee for thy arrogance.

**QCD**

## 9. Thou shalt not annoy machine people.

- 10. Thou shalt not delay, the LHC start-up is approaching

##   B.Cox, DIS05

-   B.Cox, DIS05

## Instrumenting the 420m region 

**Instrumenting the 420m region **

- Most likely scenario : Cryogenic bypass, warm beam pipes
- First opportunity to replace 420m cryostat is in planned long shutdown after first physics runs of LHC (autumn 2008?)

- Diffracted protons emerge between beam pipes

- UK FP420 is funded for R&D (including 3D silicon detector research)
- Belgium FP420 is funded for R&D (detector mechanics and electronics)
- Negotiations in progress for cryogenic engineer to design prototype 420m cryostat (in collaboration with AT-CRI group at CERN and UK Cockcroft Institute)
- FP420 meeting at CERN May 30th - 31st. Video available. Aim for LOI to LHCC at end of June. All welcome (Contact Brian Cox / Albert De Roeck / Mike Albrow (US)) .
- FP420 is not a ‘collaboration’. It is an R&D project which will hopefully lead to new sub-detectors for ATLAS and / or CMS.