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V.A. Khoze (IPPP, Durham)

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

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Forward Proton Taggers as a gluonic Aladdin’s Lamp (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 FPTWould 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

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KMR predn of (pp p + H + p)

contain Sudakov factor Tg which exponentiallysuppresses 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

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Implemented in ExHume MC

(High sens. to str. functs)

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

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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……

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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)

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☻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)

•

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

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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 )

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Theoretical Input

a ‘simplest’ extension of the minimal Higgs sector

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(h SM-like, H/A- degenerate.)

GOOD NEWS!

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● Hbb in the high mass range (MA180-250 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, Hbb, 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

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Ongoing studies

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

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● h,H in the low mass range (MA<180 GeV)-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 casein 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

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Hbb PRELIMINARY

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Current understanding of the bb backgrounds for CED production (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/B1 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 )

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The complete background calculations are still in progress (unusually large high-order QCD and b-quark mass effects).

Optimization, MC simulation- still to be done

Mass dependence of the SM(CEDP): SH~1/M³ Bkgd : ΔM/M for ,

ΔM/M for

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

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

14Adapted from a preliminary plot of HKRSTW. (M. Tasevsky)

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Hunting the CP-odd boson, A

(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)

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within the (MS) MSSM, 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

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A

in this extreme case : (Agg) Br(Abb) 22-24 MeV at MA=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) / MCD

5.5 /MCD (GeV)

currently MCD ~ 20-30 GeV…(12GeV at 120 GeV)

Prospects of A- searches strongly depend, in particular, on the possible progress with improving MCD 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

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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.