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Fermiophobic Higgs

Fermiophobic Higgs. Drew Baden University of Maryland Dzero Collaboration EPS 2003. Fermilab Tevatron. Chicago . Booster. CDF. DØ. Tevatron. p sou rce. Main Injector (new). Run I 1992-96 about 100 pb -1 recorded 1.8TeV cm energy 3.6 m s bunch crossing MainRing

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Fermiophobic Higgs

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  1. Fermiophobic Higgs Drew Baden University of Maryland Dzero Collaboration EPS 2003

  2. Fermilab Tevatron Chicago  Booster CDF DØ Tevatron p source Main Injector (new) • Run I 1992-96 • about 100 pb-1 recorded • 1.8TeV cm energy • 3.6ms bunch crossing • MainRing • Synchrotron injector for Tevatron • In same tunnel  • Run II 2001-… • 1.96TeV cm energy • 396ns bunch crossing • MainRing pulled, Main Injector built • $230M project

  3. D Detector • Upgrades: • 2T Solenoid • >100k scint. fibers • >700k silicon strips • Muon detector improvements • Preshower added • CAL, Muon, trigger electronics • NO MAIN RING!!! Silicon tracking out to h~2 Yields

  4. Run 2 Data Taking Run I total Delivered for Physics

  5. Higgs – Current Understanding • Discovery motivation is obvious • Higgs is a central part of the Standard Model • But after discovery, the Higgs mass must be determined • MHIGGS determines decay G, and sproduction for coupling to all particles • Constraints on MHIGGS ElectroWeakWorkingGroup • Favors light higgs, 91GeV central value • M<211 GeV 1-sided 95%CL LEP direct search • M>114GeV @ 95% CL

  6. What is Fermiophobic Higgs? • Fermiophobic…means you turn off couplings to fermions • Can occur in Type-1 2-doublet Higgs models • Type-1 – one doublet couples to fermions, the other to bosons • CP even neutral Higgs bosons, light h and heavy H • scalar field mixing angle a • coupling to fermions via • mass, as usual, and • sin(a) for H and cos(a) for h • h is therefore “fermiophobic” in the limit a→p/2 • Of course we could have a “fermiophobic” H (a→0)…but h is lighter so we look there…

  7. Fermiophobic Higgs Production h h t W*/Z* W/Z h W+ W- • Effect on Higgs production: • Eliminates gluon fusion • Biggest contribution to SM Higgs production…  • Leaving: • “Associated Production” • Virtual W*/Z* → onshell W/Z+h • WW fusion • Quark lines radiate W’s, fuse to h • ZZ fusion too small by usual EWK factor

  8. Fermiophobic Higgs Decay h w h w SM Branching Fractions • Final states: • No bb in the final state (fermiophobic!) • gg • Through W triangle loop • Dominates at low Mh • Also WWgg vertex • Suppressed by ~1/137 • Associated Production: • Z/W+h where h → WW/ZZ • But h →ZZ suppressed • Dominant final states are • ZWW, WWW • Physics background from ZWW, standard EWK tri-linear coupling • h → WW dominates at high Mh • LEP Combined Fermiophobic limit • Mh < 108.2 GeV @ 95% CL using h →gg mode MH< 114.4 EWWG LEP Higgs Working Group benchmark model Mh< 108.2 LHWG Note 2001-8 Hep-ex (0107035) 2001

  9. Experimental Limits • LEP Combined Fermiophobic limit • Mh < 108.2 GeV @ 95% CL using h →gg mode • LHWG Note 2001-8 and Hep-ex (0107035) 2001 • D/CDF Run1 limit 78.5 / 82.0 GeV at 95% CL • B.Abbott et al. Phys. Rev. Lett. 82, 2244 (1999 ) • F.Abe et al. Phys. Rev. D59, 092002 (1999) LEP

  10. This Talk…. • So, for this talk, present status on: • W*/Z* → W/Z h, h → WW • Look for the h → WW • Focus on final states with 2 W’s • 2 Z’s will be relatively suppressed (see previous slide) • Search for inclusive e+e-, m+m-, and em± lepton pairs + MET • The “prompt” W/Z in final state… • No requirement on any leptonic decay • W/Z*h→ W/Zgg • Look for states with 2gs • large MET and/or jets • Let the theorists foot the bill as to interpretation • Which particular “Type” etc.

  11. H → W+W-→ l+l-nn • Data: • Dielectron sample: 44pb-1 • em sample: 34p-1 • Backgrounds • ee Dominated by Z → e+e- • Reduced via MET cut • Some t’s remain • All dilepton channels have • WW/Wg/ZZ/WZ • top • W+jet and QCD misidentification

  12. Electron ID Z sample MC • Electron ID requirements • Triggered • Isolation+EMF+Shower Shape • e = 85% (93%) efficiency for central (endcap) • Track match via C2(E/p and Df) and DCA • e=73% obtained using sample of Z → e+e- • Leading electron PT>20 GeV, 2nd electron PT>10 GeV • Reduces multijet background

  13. Muon ID, Jets, and MET • Muons: • Isolated from jets • Calorimeter energy: E(DR<0.4) - E(DR<0.1)<2.5GeV • SPT (in cone DR<0.5) tracks < 2.5 GeV • Reject cosmics via timing requirement • PT > 10 GeV • Central track match • Jets: • Cut to eliminate hot towers, other pathologies • EMF cut • |h|<2.5 • Energy corrections, cone 0.5 • MET • Use calorimeter cells • Correct for jet energy corrections • Use 0.7cone jets for this

  14. Event Cuts • Electrons • 2 with PT> 20 GeV • at leats 1 with track match • M(e+e-) < 78 GeV to reject Z’s • MET • MET > 25 GeV and Df(jets,MET) > 0.5 • Dominant background is W+jets • Spin Correlations • W+ and W- have opposite spin projections • Tendency for charged leptons to be emitted along same direction • Require Df(leptons)<2.0 Higgs WW QCD Top W+g Z→ee W+jets Z→tt Df(l+l-)

  15. e+e- Final State • Dominant background from Z → e+e- • Invariant mass cut M(e+e-)<MH/2 for limit calculation • 96% effecienty for MH=160GeV • Further MET cuts to reduce jet-induced MET • Transverse mass cut MT<MH+20 GeV • Both electrons have PT>20 GeV M(e+e-) before cuts M(e+e-) after electron selection and PT cut

  16. e+e- Result • Data after all cuts… • Monte Carlo • Pythia 6.202 + full sim/reconst. • 0.5min bias overlay • Multijet backgrounds from data • Require poor electron, study… • Higgs signal • Efficiency vs. MH • Backgrounds vs. Data • largest uncertainty is in W+jets and Z(ee) Df(ee) MC/Data Comparison Selection optimized for MH=160

  17. em± Final State and Results • Comparison with e+e- analysis • No Z decay background • No transverse mass cut applied • MET cut constant: MET > 20 GeV • Less QCD multi-jet background • MET and PT(m) not aligned • All other cuts are the same • Efficiencies: • Backgrounds mostly W+jets • Results combing e+e- and em± • Upper limit of 2-3pb @ 95%CL • Limited data…x4 being analyzed now • Need ~10fb-1 to be sensitive up to Mhiggs=160 GeV sBr(H →WW → e+e-/ em± )

  18. m+m- Final State PT(m) m(m+m-) Df(jet,MET) MET Df(m+m-) MT • 48pb-1 analyzed • 2 High PT isolated muons (|h|<2) • Same cuts as previous • M(m+m-), PT(m), MET, Df(MET,jet),MT, Df(m+m-) • MC samples from Pythia 6.202, full sim/reconst • Same as for previous study • QCD and W+jets backgrounds from data • using muon isolation • Normalized to Z→mm • Overall signal efficiency for Mh=160 GeV is 14.6 ± 0.6%

  19. m+m- Result • 1 Event remains • 48pb-1 data • 14.4% overall efficiency for 160 GeV Higgs • 0.32 ± 0.01 expected from backgrounds • No official upper limit on sBr yet… • Will be reporting combined H → WW → e+e-, m+m-, and em± on 120pb-1 very soon

  20. H → gg + X • 52pb-1 analyzed • Topcolor model also considered • Fermiophobic except for top • Photon id: • EMfraction>0.9 , Shower shape C2, isolation, PT>25 GeV, charged track veto • “Fake” photons due to • high PTp0→gg (small opening angle) • Drell-Yan + tracking inefficiency • jet fluctuations mimic photon (high EMfraction) • non-prompt QCD photons QCD

  21. H → gg + X Result Central Photons • Interesting to also consider TOPCOLOR • Technicolor extension, fermiophobic except for top quark loops • Assume Br(h → gg) = 1 • Starts to get interesting at 120 GeV!

  22. LEP excluded at 95% C.L. Tevatron Higgs Working Group • The Higgs discovery potential for Run II has been evaluated (hep-ph/0010338, using a parameterized fast detector simulation) • Discovery at 3-5 can be made • Combine all channels, data from both D0 and CDF • Improve understanding of signal and background processes • b-tagging, resolution of Mbb • Advanced analysis techniques are vital • Largest luminosity required to discover Higgs • Results of simulations consistent with SHWG expectations

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