1. 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. 2 The Large Hadron Collider (LHC) PP collisions at  s = 14 TeV 5 experiments 25 ns bunch spacing  2835 bunches 10 11 p/bunch Design Luminosity: 10 33 cm -2 s -1 -10 34 cm -2 s -1  100 fb -1 /year 23 inelastic events per bunch crossing TOTEM In LEP tunnel (circonf. 26.7 km) Planned Startup: Summer 2007

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

4. 4 Roman pot acceptances - t=10 - 1 -t=10 -2 High  * (1540m): Lumi 10 28 -10 31 cm -2 s -1 >90% of all diffractive protons are seen in the Roman Pots. Proton momentum measured with a resolution ~10 -3 Low  *: (0.5m): Lumi 10 33 -10 34 cm -2 s -1 220m: 0.02 <  < 0.2 300/400m: 0.002 <  < 0.02 (RPs in the cold region/FD420 under discussion in CMS/ATLAS) TOTEM (ATLAS) FD420

5. 5 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=10 29 cm -2 s -1 : 100 million minimum bias events, including all diffractive processes >90% of all diffractive protons are detected microstation at 19m ? RPs Total TOTEM/CMS acceptance (  * =1540m) CMS/TOTEM is the largest acceptance detector ever built at a hadron collider TOTEM+CMS T1,T2 Roman Pots Charged particles Energy flux CMS/TOTEM Study

6. 6 Diffraction at LHC: PP scattering at highest energy Soft & Hard Diffraction  < 0.1  O(1) TeV “Pomeron beams“ E.g. Structure of the Pomeron F( ,Q 2 )  down to ~ 10 -3 & Q 2 ~10 4 GeV 2 Diffraction dynamics? Exclusive final states ? Gap dynamics in pp presently not fully understood! proton momentum loss measured in RPs

7. 7 H gap -jet  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 p p Mh² measured in RP via missing mass as ξ1*ξ2*s bb: Jz=0 suppression of gg->bb bg | WW: bg almost negligible E.g. V. Khoze et al M. Boonekamp et al. B. Cox et al. … V.Petrov et al. Advantages of Exclusive: 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. (Wˉ) (W+)

8. 8 DPE Higgs event generators 1.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. 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. 10 From Tevatron to LHC

11. 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. 12 FAMOS: Jet Energy Scale Correction 0 < |η jet | < 11 < |η jet | < 2 2 < |η jet | < 3|η jet | > 3

13. 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. 14

15. 15

16. 16 Mh acceptance Relative differences between models decrease with Mh (from 40% to 15% for 420+220 comb.)

17. 17 H->bb, mh=120 GeV: Protons

18. 18 H->bb, mh=120 GeV: Protons

19. 19 H->bb, mh=120 GeV: Higgs More central rapidity distr. of ExHuMe due to gluon distr. falling faster than Pomeron param. in DPEMC

20. 20 H->bb, mh=120 GeV: b-quarks after FSR

21. 21 H->bb, mh=120 GeV: hadron level

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

23. 23 H->bb, mh=120 GeV: detector level b-jets

24. 24 H->bb, mh=120 GeV: detector level

25. 25 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 1)N jet > 1 2) 45 30 GeV 3) | η j1,2 | < 2.5 4) | η j1 -η j2 | < 1.8 5) 2.8 < | φ j1 -φ j2 | < 3.48 The cuts still 6) M j1j2 / M tot > 0.75 being optimized 7) M j1j2 / M miss.mass > 0.8 8) N part (3 < | η | < 6) = 0 9) 117 < M miss.mass < 123 GeV 10) Both jets b-tagged (~40% total efficiency) Generator σ xBR[fb] Acceptance gg->H->bb BG(gg->bb;gg->gg) DPEMC 2.0 50% EDDE 1.3 46% UNDER STUDY ExHuMe 1.9 57%

26. 26 ExHuMe: H->WW, mh=140 GeV: leptons

27. 27 ExHuMe: H->WW, mh=140 GeV: quarks

28. 28 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| 14 GeV, |η|<2.1) or -1e (pt>20 GeV, |η| 25GeV,|η|<5) or -1μ (pt>10 GeV, |η| 25GeV, |η|<5) -Fully leptonic W decay: -2e (pt>17 GeV, |η| 3 GeV, |η|<2.1) or -eμ (pte>17 GeV, |η| 3 GeV, |η|<2.1) or -2e (ptmax>29 GeV,|η| 14 GeV,|η|<2.1) or -eμ (pte>29 GeV, |η| 14 GeV, |η|<2.1)

29. 29 Excl. DPE H->WW: Event yield for L=30 fb-1 ExhuMe 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 3 3.8 150 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

30. 30 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…