# Presentation: 890895

## main aim:      to show that the Central Diffractive Processes

- main aim:     ** **to show that the Central Diffractive Processes
-                           may provide an exceptionally clean environment to search
-                           for and to identify the nature of Higgs bosons at the LHC

**FP-420**

-          Diffractive processes as a tool for testing the MSSM Higgs sector at the LHC

- (in collaboration with S. Heinemeyer,  M. Ryskin, W.J. Stirling, M. Tasevsky and G. Weiglein )

**H**

##  ‘Threshold Scan’:  ‘Light’  SUSY ...                                         KMR-02 , M.Boonekamp et.  al.

-                        (Old and New Physics menu)
- Higgs Hunting  (the LHC ‘core business’)         Bialas & Landshoff -91     K(KMR)S- 97-06, M.  Boonekamp et al, V.Petrov et al,
-                                                                                                                                                                                                   E.Levin et al,   B.Cox et al, J.Ellis et al.
- Photon-Photon, Photon - Hadron Physics                       KMR-02,  A.Bzdak et al
-  **‘****Threshold Scan****’:**  ‘Light’  SUSY ...                                         KMR-02 , M.Boonekamp et.  al.
- Various aspects of Diffractive Physics (soft & hard ).     KMR-01 , K. Goulianos
- High intensity **Gluon Factory** (underrated  gluons)                 KMR-00, KMR-01
- QCD test reactions,  dijet P-luminosity monitor
- Luminometry                                                             R. Orava+KMR-01
- Searches for new heavy gluophilic states                          KMR-02, KMRS-04,  J.Forshaw et al
**                                         ****FPT**
****Would provide a unique  additional tool  to complement the conventional       strategies at the LHC and ILC.
- Higgs is only a part of the broad EW, BSM and diffractive program@LHC
-  wealth of  QCD studies,  glue-glue collider, photon-hadron, photon-photon interactions...

**FPT  ******** ****will open up**** ****an ****additional**** rich**** ****physics menu **** ILC@LHC**

## KMR predn of (pp  p + H + p)

- KMR predn of (pp  p + H + p)

- contain Sudakov factor Tg which exponentially
- suppresses infrared Qt region  pQCD

- S2 is the prob. that the rapidity gaps survive population  by secondary hadrons  soft physics  S2=0.026 (LHC)  S2=0.05 (Tevatron)

- (pp  p + H + p) ~ 3 fb at LHC       for SM 120 GeV Higgs

- H

- Implemented  in ExHume MC

- (High  sens. to str. functs)

- recent activity- J.Bartels et al- Hard Diffr.  Contrib.

##    (gg)CED     bb  in  LO ; NLO,NNLO, b- mass  effects - controllable.

-        The main advantages of** ****CED** Higgs production
- Prospects for high accuracy mass measurements
-       (irrespectively of the decay mode).
- Quantum number filter/analyser.
-       ( 0++ dominance ;C,P-even)
- H ->bb opens up (Hbb- coupl.)
-    (gg)CED   ****  bb  in  LO ; NLO,NNLO, b- mass  effects - controllable.
-  For some  areas of the MSSM param. space **CEDP** may become a** ****discovery channel** **!**
**H**** **→**WW*****/****WW  - ****an added value  **(** **less challenging experimentally + small bgds**.)****           **
- New   run of the MSSM studies  is underway.
-  New leverage –proton momentum correlations    (probes of QCD dynamics ,  CP- violation effects...)

******  **LHC : ‘after discovery stage’,  Higgs ** ID**......

**H**

- How do we know what we’ve found?

-        mass, spin, couplings to fermions  and Gauge Bosons,  invisible modes...
-        for all these purposes  the CEDP will  be particularly  handy !

**FP420** (B. Cox)

## ☻Experimental Advantages
Measure the Higgs mass via the missing mass technique
    Mass measurements do not involve Higgs decay products
    Cleanness of the events  in the central detectors.

         Experimental Challenges
Tagging the leading protons
Selection of exclusive events & backgrounds
Triggering at L1 in the LHC experiments.
 bb-mode requires special attention. 

 Uncertainties in the theory
(Unusually& uncomfortably) large higher-order effects, 
 model   dependence of predictions (soft hadronic physics is involved after all) 

                                                          

- Measure the Higgs mass via the missing mass technique
-     Mass measurements do not involve Higgs decay products
-     Cleanness of the events  in the central detectors.
-          Experimental Challenges
- Tagging the leading protons
- Selection of exclusive events & backgrounds
- Triggering at L1 in the LHC experiments.
-  bb-mode requires special attention.
-  Uncertainties in the theory
- (Unusually& uncomfortably) large higher-order effects,
-  model   dependence of predictions (soft hadronic physics is involved after all)
-                                                         ****

- There is still a lot to learn from present and future Tevatron diffractive data   (KKMRS- friendly so far).

- Talks by  R.Orava,  B. Cox, M.Tasevsky

- Talks by K. Goulianos & M. Gallinaro

## 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     ( B.Cox et al 03,  KMR-03;  J. Ellis et al -05)
- Potentially  of great importance for electroweak baryogenesis
-  an ‘Invisible’ Higgs    (BKMR-04)

-  NMSSM ( with J. Gunion and A. De Roeck )

## Theoretical  Input

- a ‘simplest’ extension of the minimal Higgs sector

## (h  SM-like,  H/A- degenerate.)

- (h  SM-like,  H/A- degenerate.)

**GOOD NEWS!**

## ●  Hbb in the high mass  range  (MA180-250  GeV)

- -**unique signature for the**** MSSM**,
-  cross-sections overshoot the SM case by orders of magnitude.
- -possibility to measure the Hbb Yukawa coupling,
- -nicely  complements the conventional Higgs searches
- - CP properties, separation of H from A,
- unique mass resolution,
- -may open a possibility to probe the ‘wedge region’ !?
- -further improvements needed ( going to high lumi ?....)
-   (more detailed  theoretical studies required )
- ● h, Hbb, in the low mass range (MA < 180 GeV)
-    -coverage mainly in the large tan  and low MA region,
-   -further improvements (trigger efficiency....) needed  in order to increase
- coverage
- -

- Ongoing studies

- ( S.Heinemeyer, V.A. Khoze , W.J.Stirling, M. Ryskin, ,M. Tasevsky and G. Weiglein )

## At the moment the situation looks borderline

- essentially bkgd –free production,
- need further improvements, better understanding..,
- -possibility to combine with the bb-signal
- (trigger cocktail ...)
- -can we trigger on  without the RP condition ?
- ● h WW
-   -significant (~4) enhancement as compared to the SM case
- in some favourable regions of the MSSM parameter space.
- ● small and controllable backgrounds
- ● Hunting the CP-odd  boson, A
- a way out : to allow incoming protons to dissociate  (E-flow ET>10-20 GeV)      KKMR-04
-          pp p + X +A +Y +p
- At the moment the situation looks borderline

##  Hbb

-  Hbb

**PRELIMINARY**

## for reference purposes SM (120 GeV)Higgs  in terms of S/B ratio (various uncrt. cancel)

-                            (Myths & Reality)

- for reference purposes SM (120 GeV)Higgs  in terms of S/B ratio (various uncrt. cancel)

-       First detailed studies by De Roeck, Orava +KMR, 2002)

-     Preliminary results  – work still in progress

- S/B1  at ΔM 4 GeV

- Four main sources (~1/4 each)

-  gluon-b misidentification (assumed 1% probability)    Prospects to improve in the  CEDP
-                                                                                         environment ? Better for larger M.
-  NLO  radiative contributions                              Correlations, optimization -to be studied.
-      (off ‘active’  &  screened gluons).
-  admixture of |Jz|=2 contribution;
-     mass- unsuppressed, cut-nonreconstructible  (NNLO) contributions.
- b-quark mass effects in dijet events         Further studies of the higher-order QCD
-     (most troublesome technically)                    effects-  in progress.

-           ( e.g. Non-Sudakov DL,  FKM-97 )

##   ( ΔM ,triggering, tagging  etc improving with rising M)   

-           (unusually large high-order QCD and b-quark mass effects).
****** ** Optimization, MC simulation- still to be done
-   Mass dependence of the SM(CEDP):  S**H**~1/M3
-  Bkgd :  **Δ****M/M**   for ,
-              **Δ****M/M**     for 
** ****** ( ΔM ,triggering, tagging  etc improving with rising M)

**6**

** ****8**** **

- 5 discovery plots, based on the CMS Higgs Group procedure- HKRSTW,
-                              (on the conservative side)

## Adapted from a preliminary plot of HKRSTW.

- Adapted from a preliminary plot of HKRSTW.

- (M. Tasevsky)

## Slide 15

##   challenges: bb mode – bkgd conditions    -mode- small (QED)bkgd, but low Br

- (LO) selection rule – an attractive feature of the CEDP processes,   but......
**** the flip side to this coin:
-      strong ( factor of ~ 102 )suppression  of the CED  production of the A boson.
- A way out : to allow incoming protons to dissociate  (E-flow ET>10-20 GeV)      KKMR-04
-          pp p + X +H/A +Y +p          (CDD)

- in LO azim. angular dependence:  cos2 (H), sin2 (A),  bkgd- flat

****** ** challenges: bb mode – bkgd conditions    -mode- small (QED)bkgd, but low Br

- A testing ground for CP-violation studies in the CDD processes (KMR-04)

##  ‘best case’ (extreme) scenario

-         e.g. mh         scenarios with  =±200 (500) GeV,  tan=30-50
-   CDD(A->bb) ~ 1-3 fb,     CDD(A->) ~ 0.1-03  fb                   CDD(H)~-CDD(A)

-  max

- bb mode –challenging bkgd conditions (S/B ~1/50).
- -mode- small (QED) bkgd, but low Br
- situation looks borderline  at best

-  ‘best case’ (extreme) scenario
- mh        with       =-700 GeV , tan  =50, mg  =103GeV

- max

- CDD results at  (RG) >3,  ET>20 GeV

##                                     CDD (A bb) is decreasing from 65fb to 25fb  (no angular cuts) 

**A**** ******** **

- in this extreme case :  ******(A********gg) Br(A********bb)**** ******** ****22-24**** ****MeV**** at M****A****=****160-200**** ****GeV ,tan******** ********50**,
-                                     CDD (A bb) is decreasing from 65fb to 25fb  (no angular cuts)
-                                ******  ******CDD (**A**)  0.8-0.3 fb

**S/B ~ ********(A->gg) Br (A->bb) /******** M****CD**
-            **5.5 /********M****CD**** ****(GeV)**
- currently ******M****CD**** ~ 20-30 GeV**...
- (12GeV at 120 GeV)
- Prospects of  A- searches
- strongly depend, in particular, on the possible progress with improving ******M****CD**
- in the Rap. Gap environment

- There is no easy solution here, we must work hard in order to find way out .

- We have to watch closely the Tevatron exclusion zones

## CONCLUSION

-  **FPT** has the potential to make measurements which are unique at LHC  and challenging even at a ILC.
- For some MSSM  scenarios the **FPT** may be the Higgs  discovery channel.
- ** ****FPT** offers a sensitive probe of the CP structure of the
-    Higgs sector.