1 / 40

Midterm Meeting, 11-13 October, 2004

Midterm Meeting, 11-13 October, 2004. Exclusive Diffractive Higgs Production and Related Processes. V.A. K hoze ( IPPP , Durham ) & PNPI ( St.Petersburg). In collaboration with A.B. K aidalov, A.D. M artin ,M.G. R yskin, W.J. S tirling. Main Aims :

dmoser
Download Presentation

Midterm Meeting, 11-13 October, 2004

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Midterm Meeting, 11-13 October, 2004 Exclusive Diffractive Higgs Production and Related Processes V.A. Khoze (IPPP, Durham) & PNPI(St.Petersburg) In collaboration with A.B.Kaidalov, A.D.Martin ,M.G.Ryskin, W.J.Stirling • Main Aims: • to illustrate how the Higgs physics reach of the LHC can be significantly extended by addition • of Forward Proton Taggers. • to discuss the Standard Candles for testing • the theoretical predictions. • .

  2. CMS &ATLAS were designed and optimised to look beyond • the SM • -> High pt signatures in the central region • But… • Main physics ‘goes Forward’ • 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 • Photon –photon reactions we♥ILC p p RG Is there way out? ☺ YES-> Forward proton tagging Rapidity Gaps Hadron Free Zones Δ Mx ~δM (missing mass) X RG p p

  3. PLAN • 1. Introduction • (a gluonic Aladdin’s lamp) • 2. The key selling points of the Central • Exclusive Diffractive processes. • 3. Basic elements of the KMR approach • (a brief guide) • 4. Prospects for CED Higgs production. • the SM case • MSSM Higgses in the troublesome regions • MSSM with CP-violation • 5. Experimental checks (today and tomorrow) • 6. New recent development • 7. Conclusion

  4. Forward Proton Taggersas a gluonic • Aladdin’s Lamp • Rich Old and New Physics menu • Higgs Hunting (currently a key selling point). • Photon-Photon Physics. • ‘Light’ SUSY ( sparticle ‘threshold’ scan). • Various aspects of Diffractive Physics • (strong interest from cosmic rays people). • Luminometry. • High intensity Gluon Factory. • (lower lumi run, RG trigger…) • Searches for new heavy gluophilic states • (radions ,gluinonia,….), KK gravitons.. • Would provide a unique additional tool • to complement the conventional • strategies at theLHCandILC. • (a ‘ time machine’) • Not as ‘either the Higgs or nothing’

  5. The advantages of CED Higgs production • Prospects for high accuracy mass • measurements (ΓH in some MSSM cases) • mass windowM = 3 ~ 1 GeV (a wishlist) • ~4 GeV(currently feasible, Helsinki Group) • Valuable quantum number filter/analyser. • ( 0++dominance ;C,P-even) •  No obvious way toestablish theHiggsCP • 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 ->studied • SM HiggsS/B~3(1GeV/M) • complimentary information to the • conventional studies( also tau tau) • H->WW*,especially for SM Higgs with M≥ 135GeV • New leverage –proton momentum correlations • (probes of QCD dynamics, pseudoscalar ID, • CP violation effects.)

  6. The basic ingredients of the KMR approach(1997-2004) Interplay between the soft and hard dynamics Sudakov suppression • 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

  7. MIND THE GAP high price to pay for such a clean environment (CEDP) ~ 10-4(INCL) Rapidity Gaps should survive hostile hadronicRadiation Damages & ‘partonic pile-up’ W = S2 T2 • Colour charges of the ‘digluon dipoles’ are • screened only at r> 1/<Qt> • GAP KEEPERS(survival factors), • protecting RG against: • the debris of QCD radiation with M>kt>Qt(T) • soft rescattering effects (necessitated by unitarity) (S) Forcing two (inflatable) camels to go through the eye of a needle

  8. schematically skewed unintegrated structure functions (suPDF) (x’~Qt/√s) <<(x~ M/√s) <<1 (Rg=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 ( theapparent divergency in the Qt integration nullifies) <Qt>SP~M/2exp(-1/αs),αs =Nc/παsCγ SM Higgs, <Qt>SP ≈ 2 GeV>> ΛQCD

  9. MAIN FEATURES • An important role of subleading terms in fg(x,x’,Qt²,μ²), • (SL –accuracy). • Cross sectionsσ~(fg )(PDF-democracy) • S²KMR=0.026 (± 50%)SM Higgs at LHC • (detailed two-channel eikonal analysis of soft pp data) • Good agreement with other ‘unitariser’s approaches and MCs. • S²/b² - quite stable (within 10-15%) • S²~ s(Tevatron-LHC range) • dL/d(logM² ) ~ 1/ (16+ M) • σH ~ 1/M³ , (σB) ch ~ Δ M/ M 4 ^ ^ ^ ^ -016 3.3 6 • Jz=0 ,even P- selection rule forσis justified only if <pt>² /<Qt>² « 1

  10. Current consensus on the LHC Higgs • 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 MSSMh-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

  11. SM Higgs, CEDP LHC, L=30fb-1 KMR-00,KKMR-03 M(GeV) 120 140comments accuracy σ 3fb 1.9fbcould be improved (1 -5.5fb)(0.6-3.5fb)(th. exp. CEDPdijets Mjj~M) Sbb11 3.5cuts +effi.s (S/B)bb3(1GeV/M) 2.4(1GeV/ M)cuts +effis. LO,NLO Bgd Sww* 3.68.4 LH,LL domin. . 6 (MC+det. sim) ADR & MSdetailed MC needed (S/B)ww* >>1 >>1detailed MC studies needed ZZ*+tau tau

  12. ‘Natural’ low limit - 0.1fb(photon fusion) • ☺An added value of the WW* • ‘less demanding’ experimentally • (trigger and mass resolut. requirements..) • high acceptances and efficiencies • an extension of well elaborated conventional program, • (existing experience, MC’s………) • (studied backgrounds: pure QED, gg->qqW, gg-WW*…) • Note in passing: • mass resolution is rising with M • prospects of accurate H mass measurements , • 0+ assignment ,spin-parity analyzing • - still hold

  13. 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) • The MSSM with explicit CP violation (A.Pilaftsis,98;M.Carena et al.,00-03,B.Cox et al 03)

  14. Higgs couplings (G.Weiglein)

  15. (a )The intense coupling regime • MA≤ 120-150GeV, tanbeta >>1( E.Boos et al,02-03) • h,H,A- light, practically degenerate • large wdths, must be accounted for • the ‘standard’ modes WW*,ZZ*, gamma gamma …- • strongly suppressed v.s. SM • the best bet –mu mu channel, • In the same time – especially advantageous for CEDP: ☺ • (KKMR 03-04) • σ(Higgs->gg)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 beta < 5-10 • (the LHC wedge, windows) • (c) The decoupling regime • (in reality, MA>140 GeV, tan beta >10) • h is SM-like, H/A -heavy and approximately degenerate, • CEDP may allow to filter Aout ~ ~

  16. The intense coupling regime of the MSSM The intense coupling regime is where the masses of the 3 neutral Higgs bosons are close to each other and tan b is large suppressed enhanced 0++ selection rule suppresses A production: CEDP ‘filters out’ pseudoscalar production, leaving pure H sample for study for 5 s with300 (30) fb-1

  17. decoupling regime: mA ~ mH large h = SM intense coup: mh ~ mA ~ mH ,WW.. coup. suppressed • with CEDP: • h,H may be • clearlydistinguishable • outside130+-5 • GeV range, • h,H widths are quite different

  18. 5signal at LHC 30 fb-1 300 fb-1

  19. SMpp  p + (Hbb) + p S/B~11/4(M) with M (GeV) at LHC with 30 fb-1 e.g. mA = 130 GeV, tan  = 50 (difficult for conventional detection, but CEDP favourable) S B mh = 124.4 GeV 71 3 mH = 135.5 GeV 124 2 mA = 130 GeV 1 2 X M 1 GeV incredible significance(10 s.d.) for Higgs signal even at 30 fb -1

  20. The intermediate regime. The ‘LHC window’. With CEDP the mass range up to 160-170 GeV can be covered at 300 fb-1

  21. pp->p+H+p Higgs An additional valuable tool A(0-), CPX More IR-sensitive

  22. more peripheral p1T,p2T correlations reflect spin-parity of central system: can distinguish 0- from 0+ pp->p1+H+p2

  23. Probing CP violation in the Higgs Sector A ‘CPX’ scenario KMR-04 CP even

  24. X M 1 GeV 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 scenario • 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 b = 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

  25. EXPERIMENTAL CHECKS • 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) • ‘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 shapeof the • distribution) • The ratio of high Et dijets in production with one • and two rapidity gaps • The HERA data on diffractive high Et dijets in • Photoproduction. • (Klasen& Kramer-04 NLO analysis) • Preliminary CDF results on exclusive charmonium • CEDP. Higher statistics is on the way. • Energy dependence of the RG survival (D0, CDF) • (…..in the time of writing has still survived theexclusion limits • set by the Tevatron data…. (M.Gallinaro, hep-ph/01410232)

  26. KMR-00 CEDP ~ 1 nb KMR-04 ~40pb ‘OPTIMISTIC ‘ models ruled out experimentally (Run I-published , Run II, prelim) More tests with upcoming Tevatron run-II data

  27. Test of factorization understood in terms of rescattering corrections

  28. CDF-00 KKMR-01 The measured CDF dijet diffractive distributioncomparedwith KKMR predictions

  29. Soft survival factors for RG no inelastic interaction.

  30. Diffractive dijet production ,Tevatron KKMR-03 KMR-00, prediction A.Bialas& R.Pecshanski 03 2 K.Goulianos 2 2 2 2

  31. Possible “standard candles” C,b

  32. Diffractive  production KMR+Stirling (KMR-01,KMRS-04) also Petrov &R.Ryutin-04 only (order-of-magnitude) estimates possible forcharmonium production

  33. KMR-01, 70 pb

  34. KMRS - 04 KMRS

  35. “Standard Candles” at Tevatron to test excl. prod. mechanism ppp +  + p high rate, but low scale (uncertainties in the estimates) ppp + jj + p rate rather high, but exclusive peak may be washed out ppp + + p low rate, but cleaner signal

  36. Some recent development • …Fromthe myth about the‘wide range of predictions • to the realities of calculations… • Sensitivity studies of the uPDFs to the details ofthegluon kt-distribution • (L.Lonnblad & M.Sjodalh,03 ,H.Jung) • The bottom line: currently - mainly • kt- integrated gluon densities are tested. • The PYTHIA MC result for the soft • Gap Survival factor (LHC)=0.026. • (L.Lonnblad, March 04 ) DKS-1992 • bj, KKMR, GLM, M.Strikman et al -analytical results • Correlations between the proton pt’s - a way to probe the dynamics of diffraction (unitarity effects) and the properties • of the central system • (K(KMR) 02-04; A. Kupco et al 04; • V.Petrov et al, 04). • A (simple) model for CEDP with gluon • uPDF fitted to HERA elastic data. • (DL Sudakov and unitarization included) • (V.Petrov & R.Ryutin,04)

  37. MC and detector simulation studies • (Manchester, Saclay groups, V.Petrov et al). • Studies of the possibility to observe • an ‘Invisible Higgs‘ • (KMR, 04) • Even more severe background and • trigger conditions • Fashion takes its toll • gluinonia in split SUSY scenarios • (Durham group…) depends on survival

  38. HERA Experiments: (what we would like to have for Xmas) Thanks to Aliosha, Leif, Michael and Misha main aim: to constrain un(integrated)gluonatHERA • Reanalyze dijets in photoproduction at higher ET. • Measure ratios of diffractive/inclusive crosssectionsat HERA at high ET(KMR-03)  Photon PDF uncertainties cancel  Hadronization corrections cancel • Measure FL atx=0.005-0.03, Q2=3-30GeV2 • Exclusive charmonium production (possiblehandleon the suPDF) • Inclusive photoproduction of high Et (~20-40GeV) jets in the current fragmentation region (pt-distribution)

  39. CONCLUSION CONCLUSION • Forward Proton Tagging proves to be • a promisingvaluable tool to study the Higgs • physics at the LHC. • Exclusive Diffractive Higgs Production may • provide a unique possibility to cover the • troublesome domains of the MSSM and to • verify the identity of the Higgs-like candidates. • So far Durham approach has • survived the experimental tests. • The predicted rates for New Physics • signals can be checked experimentally by theproposedStandardCandle processes. • …still a lot of studies to be done…. • FORWARD PHYSICS NEEDS FORWARD • DETECTORS • Nothing would happen unless • the experimentalists come FORWARD and do • REAL WORK

  40. Summary and work in progress • If you see a resonance with proton tags, you know its quantum numbers • Proton tagging allows excellent mass resolution • If the Higgs (or any other new particles) couple strongly to gluons, proton tagging may be the discovery channel • Proton tagging allows access to bb decay modes if good enough detector resolution can be achieved • The Monte Carlo tools are coming on stream • The detectors can be warm at 420m - cryostat redesign is cheap • It is still desirable (and possible?) to trigger directly at level 1 on 420m pots (at least at CMS) - work in progress • Central bb trigger strategies including 220m asymmetric options) under study • We (UK groups) are bidding to begin serious R&D by mid 2005

More Related