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Exclusive DPE Higgs production at LHC

Exclusive DPE Higgs production at LHC. Marek Taševský (Physics Inst. Prague + Univ.Antwerp) ISMD 2005 - Kroměříž (Czech Republic) 15/08 2005. 1. Comparison of DPEMC, ExHuMe and EDDE at parton, hadron and detector levels 2 . New Roman Pot acceptances 3 . Event yields for H->WW.

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Exclusive DPE Higgs production at LHC

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  1. Exclusive DPE Higgs production at LHC Marek Taševský (Physics Inst. Prague + Univ.Antwerp) ISMD 2005 - Kroměříž (Czech Republic) 15/08 2005 1. Comparison of DPEMC, ExHuMe and EDDE at parton, hadron and detector levels 2. New Roman Pot acceptances 3. Event yields for H->WW

  2. The Large Hadron Collider (LHC) • PP collisions at • s = 14 TeV • 5 experiments • 25 ns bunch spacing •  2835 bunches • 1011 p/bunch • Design Luminosity: • 1033cm-2s-1 -1034cm-2s-1 • 100 fb-1/year 23 inelastic events per bunch crossing In LEP tunnel (circonf. 26.7 km) TOTEM Planned Startup: Summer 2007

  3. The CMS experiment • Tracking • Silicon pixels • Silicon strips • Calorimeters • PbW04 crystals • for Electro-magn. • Scintillator/steel • for hadronic part • 4T solenoid • Instrumented iron • for muon detection • Coverage • Tracking • 0 < || < 2.5-3 • Calorimetry • 0 < || < 5 A Hugeenterprise ! Main program: EWSB, Beyond SM physics…

  4. -t=10-2 -t=10-1 Roman pot acceptances TOTEM (ATLAS) High * (1540m): Lumi 1028-1031cm-2s-1 >90% of all diffractive protons are seen in the Roman Pots. Proton momentum measured with a resolution ~10-3 Low *: (0.5m): Lumi 1033-1034cm-2s-1 220m: 0.02 <  < 0.2 300/400m: 0.002 <  < 0.02 (RPs in the cold region/FD420 under discussion in CMS/ATLAS) FD420

  5. Total TOTEM/CMS acceptance (b*=1540m) RPs microstation at 19m? CMS/TOTEM Study CMS/TOTEM is the largest acceptance detector ever built at a hadron collider For the first time at a collider large acceptance detector which measures the forward energy flow 1 day run at large beta (1540m) and L=1029cm-2s-1: 100 million minimum bias events, including all diffractive processes >90% of all diffractive protons are detected Charged particles T1,T2 T1,T2 Roman Pots Roman Pots TOTEM+CMS Energy flux

  6. Diffraction at LHC: proton momentum loss measured in RPs • PP scattering at highest energy • Soft & Hard Diffraction  < 0.1  O(1) TeV “Pomeron beams“ E.g. Structure of the Pomeron F(,Q2)  down to ~ 10-3 & Q2 ~104 GeV2 Diffraction dynamics? Exclusive final states ? • Gap dynamics in pp presently not fully understood!

  7. Double Pomeron Exch. Higgs Production Exclusive DPE Higgs production pp p H p : 3-10 fb Inclusive DPE Higgs production pp  p+X+H+Y+p : 50-200 fb -jet (W+) E.g. V. Khoze et al M. Boonekamp et al. B. Cox et al. … V.Petrov et al. gap gap H h p p -jet (Wˉ) Advantages of Exclusive: Mh² measured in RP via missing mass as ξ1*ξ2*s bb: Jz=0 suppression of gg->bb bg | WW: bg almost negligible bb: We need a L1-trigger of “central CMS+220 RP” type. Central detector is issue as CMS is not designed for low Et physics. Under study by CMS-Totem L1-tr. group WW: Extremely promising for Mh>130 GeV: no trigger problems and a better Mh resolution for higher Mh.

  8. DPE Higgs event generators • DPEMC 2.4 (M.Boonekamp, T.Kucs) - Bialas-Landshof model for Pomeron flux within proton - Rap.gap survival probability = 0.03 - Herwig for hadronization 2. EDDE 1.2 (V.Petrov, R.Ryutin) - Regge-eikonal approach to calculate soft proton vertices -Sudakov factor to suppress radiation into rap.gap - Pythia for hadronization 3. ExHuMe 1.3 (J.Monk, A.Pilkington) - Durham model for exclusive diffraction (pert.calc. by KMR) - Improved unintegrated gluon pdfs - Sudakov factor to suppress radiation into rap.gap + rap.gap survival prob.=0.03 - Pythia for hadronization All three models available now in the fast CMS simulation!

  9. Difference between DPEMC and (EDDE/ExHuMe) is an effect of Sudakov suppression factor growing as the available phase space for gluon emission increases with increasing mass of the central system Models predict different physics potentials !

  10. From Tevatron to LHC

  11. Fast CMS simulation: FAMOS Main chapters: - Fastcalorimetry, FastElgamma, FastElMatching - FastTsim, FastBtag - FastJets, FastMET, FastHLTMET - FastMuon, FastMuonTrigger - FastTotem (just Roman Pots), FastCastor Jet algorithm: o) Iterative cone o) Cone radius = 0.7

  12. FAMOS: Jet Energy Scale Correction 0 < |ηjet| < 1 1 < |ηjet| < 2 2 < |ηjet| < 3 |ηjet| > 3

  13. New Roman Pot acceptances for β*=0.55m Update of RP acceptances for recent LHC optics V6.5 (V.Avati and K.Osterberg, Totem Note 05-2) V6.5 V6.2 β*=0.55m 0.5m x*=500μm 0 μm Beam X-angle=142 μrad 150 μrad Proton trajectories simulated with MADX These acceptances recently put in FAMOS.

  14. Mh acceptance Relative differences between models decrease with Mh (from 40% to 15% for 420+220 comb.)

  15. H->bb, mh=120 GeV: Protons

  16. H->bb, mh=120 GeV: Protons

  17. H->bb, mh=120 GeV: Higgs More central rapidity distr. of ExHuMe due to gluon distr. falling faster than Pomeron param. in DPEMC

  18. H->bb, mh=120 GeV: b-quarks after FSR

  19. H->bb, mh=120 GeV: hadron level

  20. H->bb, mh=120 GeV: detector level

  21. H->bb, mh=120 GeV: detector level b-jets

  22. H->bb, mh=120 GeV: detector level

  23. Excl.DPE H->bb: Event yields per L=30 fb-1 • Selection cuts at detector level for mh=120 GeV: 0)Both protons accepted in one of two (220,420) RP stations • Njet > 1 2) 45 < Etj1*JESCor< 85 GeV, Etj2*JESCor> 30 GeV 3) |ηj1,2| < 2.5 4) |ηj1-ηj2| < 1.8 5) 2.8 < |φj1-φj2| < 3.48 The cuts still 6) Mj1j2/Mtot > 0.75 being optimized 7) Mj1j2/Mmiss.mass > 0.8 8) Npart(3<|η|<6) = 0 9) 117 < Mmiss.mass < 123 GeV 10) Both jets b-tagged (~40% total efficiency) Generator σxBR[fb] Acceptance gg->H->bb BG(gg->bb;gg->gg) DPEMC 2.0 50% EDDE 1.3 46% UNDER STUDY ExHuMe 1.9 57%

  24. ExHuMe: H->WW, mh=140 GeV: leptons

  25. ExHuMe: H->WW, mh=140 GeV: quarks

  26. Excl.DPE H->WW:Event yields per L=30 fb-1 • Both protons accepted in one of two RP’s (220, 420) • (L1 muons taken from FAMOS. El.+quarks correspond to parton level) • Various cut scenarios acc.to current CMS L1 thresholds: • Semi-leptonic W decay: • 1e (pt>29 GeV, |η|<2.5) or 1μ (pt>14 GeV, |η|<2.1) or • 1e (pt>20 GeV, |η|<2.5) + 2 quarks (pt>25GeV,|η|<5) or • 1μ (pt>10 GeV, |η|<2.1) + 2 quarks (pt>25GeV, |η|<5) • Fully leptonic W decay: • 2e (pt>17 GeV, |η|<2.5) or 2μ (pt>3 GeV, |η|<2.1) or • eμ (pte>17 GeV, |η|<2.5 and ptμ>3 GeV, |η|<2.1) or • 2e (ptmax>29 GeV,|η|<2.5) or 2μ (ptmax>14 GeV,|η|<2.1) or • eμ (pte>29 GeV, |η|<2.5 or ptμ>14 GeV, |η|<2.1)

  27. Excl. DPE H->WW: Event yield for L=30 fb-1ExhuMe 1.3 and new RP acceptances semi-lept fully-lept Mh[GeV] σXBR[fb] Acc.[%] cms atlas cms atlas Total 120 0.37 57 0.2 0 1.2 1 1.3 135 0.77 62 0.6 3.1 3.4 140 0.87 63 0.6 1 3.5 33.8 150 1.00 66 1.0 4.9 5.3 160 1.08 69 1.0 1 6.0 5 6.6 170 0.94 71 1.0 5.4 5.9 180 0.76 74 0.8 1 4.5 4 4.9 200 0.44 78 0.6 1 2.9 2 3.2

  28. Summary - Recent versions of DPEMC, EDDE and ExHuMe generators as well as new RP acceptances available in CMS fast simulation - Working on optimizing the selection cuts for H->bb and H->WW channels. The H->WW channel looks promising for Mh>130 GeV. Unlike for H->WW, the L1-trigger and background for H->bb are issues and still need a lot of work. A common CMS-TOTEM L1-trigger working group established and studying this problem intensively - Hot topic these days: Which model gives the best description of data??? The problem is that the only data available are those of Rjj distr. from CDF. More to come soon…

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