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Alexi Mestvirishvili University of Iowa Department Physics and Astronomy

Status of the qq  qq h study. Alexi Mestvirishvili University of Iowa Department Physics and Astronomy. Comments and question direct to Alexi.Mestvirishvili@cern.ch. Events generation by PYTHIA 6.1.52 Detector response simulation by CMSJET. f i f j  f i f j h

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Alexi Mestvirishvili University of Iowa Department Physics and Astronomy

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  1. Status of the qq  qqh study Alexi Mestvirishvili University of Iowa Department Physics and Astronomy Comments and question direct to Alexi.Mestvirishvili@cern.ch

  2. Events generation by PYTHIA 6.1.52 Detector response simulation by CMSJET

  3. fi fj fi fjh (Higgs production via WW fusion) Higgs mass was chosen to be 300 GeV Higgs decay hZZ Z decay Z(1) e+e- Z (2)    Two forward jets are generated after the quarks from incoming protons radiates W ‘s Signal events

  4. Background processes considered so far 2)WW ZZ 3) ZZ Z(1) e+e- Z (2)    4) Z+jet fi fi Z0 f g  f Z0 Z e+e- N number of events in each set 100000

  5. Cross-sections and luminosities (  given by PYTHIA) Tab.1

  6. Jets selection 1) All reconstructed jets must be well within CMS aperture -5 <  < 5 2) Forward jets selection 2.5 < || < 5 3) Jet transverse energy Et > 20GeV 4) At least one tagged forward jet satisfying the criteria above

  7. 1) Presence of two isolated lepton required (one electron, one positron) 2) ||(lepton) < 2.4 3) Et(lepton) > 20GeV 4) Invariant mass of two leptons must be in vicinity of Z mass --- |M(e+e-) – M(Z)| < 5GeV leptons(e+e- )selection

  8. Jets multiplicity Two jet events are dominant in the signal sample N of jets N of jets NOT NORMALIZED N of jets N of jets

  9. Forward jet multiplicity Most of the events has one forward jet in all samples N of jets N of jets NOT NORMALIZED N of jets N of jets

  10. Missing transverse energyE missdistribution t NOT NORMALIZED Z + jet events are almost completely killed by the E miss cut t Emiss>50GeV was required t Emiss (GeV) t

  11. at least 1 forward tag jet two forward tag jets each in opposite hemispheres qqh 28.63% 6.1% WW ZZ 20.05% 4.5% ZZ 1.04% 0.016% Z+jets 10-3% 0% Efficiency Tab.2

  12. Number of events Nev = ·  · L(lhc · year) where –efficiency for particular process L(lhc · year) – one year LHC running integrated luminosity  –particular process cross-section

  13. at least 1 forward tag jet at least 1 forward tag jet 2 forward tag jets each in opposite hemispheres 2 forward tag jets each in opposite hemispheres qqh qqh 41 25 6 9 WWZZ WWZZ 0.28 0.46 0.1 0.06 ZZ ZZ 30 51 0.5 0.8 Z+jets Z+jets 4048 2433 0 0 Number of events Assuming one year running at low luminosity L = 60fb-1 Assuming one year running at high luminosity L = 100fb-1

  14. t t Z Each t decays to W b with consecutive W decay to e. Z decays to e+e-. two neutrinos from W generates large missing transverse energy. Charged leptons: A) two e from W are out of tracker acceptance, two e from Z are in one electron/positron from Z and one positron/electron from one of the W are in the tracker acceptance others out Jets: C) bothb jets from t decay are forward i.e. could not be tagged as a b jets. one b central, another forward and one forward jet is generated by ISR or FSR. both b jets central, two forward jets are generated by ISR or FSR Bkg sources to be considered in near future

  15. Bkg sources to be considered in near future A) + C)—worst case scenario, final state configuration exactly as in signal events. Significantly will affect the signal to background ratio. A) + D) and A) + E)— b jet tagging will suppress this kind of configuration, but assuming b tagging efficiency is expected to be 60%-70% will contribute to the signal to background ratio. B) + C), B) + D) — in addition to the b jet tagging needs to investigate or dilepton mass distribution, in order to determine the B) + E) distribution exact shape to use side band subtraction method.

  16. Bkg sources to be considered in near future • t t • Each t decays to W b with consecutive W decay to e. two neutrinos from W • generates large missing transverse energy. • Charged leptons stays central and they are detectable. • Jets: • both b jets from t decay are forward i.e. could not be tagged as a b jets • one b central, another forward and one forward jet is generated by ISR or FSR. • both b jets central, two forward jets are generated by ISR or FSR • Needs to investigate dilepton mass distribution, in order • to determine the distribution exact shape to use side band subtraction method.

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