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Search for Fermio phobic Higgs in the h  gg Channel

Search for Fermio phobic Higgs in the h  gg Channel. DPF 2002, Williamsburg. Alex Melnitchouk (Brown University) on behalf of D0 Collaboration.

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Search for Fermio phobic Higgs in the h  gg Channel

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  1. Search for Fermiophobic Higgs in the hgg Channel DPF 2002, Williamsburg Alex Melnitchouk (Brown University) on behalf of D0 Collaboration Alex Melnitchouk DPF conference - May 2002

  2. Fermiophobic Higgs. Theoretical Outlook • Many of SM extensions predict enhanced rate for Higgs decay into photon pairsdue to suppressed couplings to • - light quarks, • - heavy quarks (TopColor) • - up-type fermions (MSSM+smth) - all fermions • Enhanced ggrate is also predicted by some models that employ Extra Dimensions as well as other Exotic models. Alex Melnitchouk DPF conference - May 2002

  3. Fermiophobic Higgs. Experimental Outlook • From Experimental Point of View it is convenient to consider gg decays of the Higgs in two extreme cases: • 1. all fermion couplings are zero (Fermiophobic Higgs) • 2. Top Quark coupling is allowed (Topcolor Higgs) Alex Melnitchouk DPF conference - May 2002

  4. hggBranching Ratio Fermiofobic Higgs some other non SM predictions Standard Model in general we should be prepared for Higgs Mass S.Mrenna, J.Wells (hep-ph/0001226) any Br(hgg) due to new physics - quote Enhancement of hgg decays Alex Melnitchouk DPF conference - May 2002

  5. Why Look for Fermiophobic Higgs at Fermilab ? • Tevatron performance offers search possibilities beyond current mass limits within next few years • In comparison with LEP there is additional possibility of Higgs production via gluon fusion  also TopColor Higgs can be looked for • D0 is working on WW and gg channels • Both analyses rely mostly on the calorimeter (most understood of all D0 sub-detectors) • Comparative Advantages : WWis predicted to have higher Branching ratio ggis a clean signature, has smaller backgrounds Alex Melnitchouk DPF conference - May 2002

  6. Cross-Section, pb-1 10.0 h t 1.0 q W(Z) 0.1 h q q 0.01 W (Z) 80 100 120 140 160 h Higgs Mass g g q Cross-Sections of Signal Production. Final States Production Processes:gluon fusion,W/Z associated, W/Z fusion •  Major final states are : - gg- gg+1 ormorejets t Alex Melnitchouk DPF conference - May 2002

  7. Major Backgrounds are QCD processes that in the final state contain : d/d Mgg , pb-1/GeV 0.1 total QCD • two real photons • one real photon and a hadronic jet that fakes a photon • two hadronic jets faking photons 0.01 gg gj 0.001 jj 0.0001 100 125 150 180 Mgg, Background Cross Sections Alex Melnitchouk DPF conference - May 2002

  8. Previous Results RunI (0.1 fb-1) D0 : gg+2 jets analysis found 4 events (expected background = 6.0 +/-2.1) set mass limit of 78.5 GeV at 95% C.L. CDF : gg+2 jets; gg+e, , MissingEt analysis found 6 events (expected background = 6.2 +/-2.1) set mass limit of 82 GeV at 95% C.L. LEP limit :108.2 GeV at 95% CL Alex Melnitchouk DPF conference - May 2002

  9. Br(hgg) RunI (0.1 fb-1) 0.5 0.2 RunIIa (2.0 fb-1) 0.1 0.05 RunIIb (30 fb-1) 0.02 0.01 100 120 140 160 180 Higgs Mass Tevatron RunII Sensitivities (gluon fusion not included) • G.Landsberg and K.Matchev(hep-ex/0001007) estimated Tevatron RunII limits on hggBranching Ratio as a function of Higgs Mass with 95%CL Preliminary LEP exclusion contour, A Andre Sopczak(hep-ph/0112082) Fermiophobic h Alex Melnitchouk DPF conference - May 2002

  10. hggBranching Ratio RunI (0.1 fb-1) 0.5 0.2 RunIIa (2.0 fb-1) 0.1 0.05 0.02 RunIIb (30 fb-1) 0.01 100 120 140 160 180 Higgs Mass Tevatron RunII Sensitivities (gluon fusion included) MSSM+smth h Alex Melnitchouk DPF conference - May 2002

  11. Something about Photon ID specifics? Not sure what to put for this Alex Melnitchouk DPF conference - May 2002

  12. Selection of gg Candidate Events • Trigger: diEM or Single EM high Pt triggers • Kinematic cuts: Pt >20GeV • Acceptance cuts: Central Calorimeter (CC) (||<1.1) or EndCap Calorimeter (EC) (1.5<||<2.4), away (0.015) from -cracks in CC • Photon ID: -0.05<Isolation<0.1, 0.95<Emfraction<1.05, shower shape consistent with EM shape (8x8 Hmatrix 2 <75), total Pt (within ||<0.1) of tracks <1.46 GeV Alex Melnitchouk DPF conference - May 2002

  13. Monte Carlo Estimate of hgg+X Efficiencies Included : ID (without 2 cut ), Acceptance NOT included : Kinematic cuts Alex Melnitchouk DPF conference - May 2002

  14. = (E(1) - E(2)) / (E(1) + E(2)) Signal and Background Monte Carlo Distributions (Some or all of these (if any) as they are or remade for double-checking their validity) Alex Melnitchouk DPF conference - May 2002

  15. di-EM Invariant Mass from 11/01-04/02 D0 data Aslo need to calculate other QCD backgrounds, (and Z?) Isolated  Candidate Events tight and loose cuts (calorimeter info only) + tracking info estimated background contribution from direct  Alex Melnitchouk DPF conference - May 2002

  16. Other plots ? In case there are any suggestions Alex Melnitchouk DPF conference - May 2002

  17. Event Display of gg Candidate (or gg+jet) ? • Do you think it is worth to pick a most “ h->gamma gamma looking ” event out of the mass distribution two slides ago and show various event displays of it? Alex Melnitchouk DPF conference - May 2002

  18. Conclusions • … Alex Melnitchouk DPF conference - May 2002

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