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FTK Studies: H hhbbbb. FTK Physics Case Meeting 12/15/05 Erik Brubaker University of Chicago. Double Higgs—Process. Resonant production of lightest MSSM neutral scalar Higgs h 0 through the heavier H 0. Previous study (ATL-PHYS-97-104)
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FTK Studies: Hhhbbbb FTK Physics Case Meeting 12/15/05 Erik Brubaker University of Chicago
Double Higgs—Process • Resonant production of lightest MSSM neutral scalar Higgs h0 through the heavier H0. • Previous study (ATL-PHYS-97-104) • For MH=300 GeV and tan(b)=3, S/sqrt(B) of 5.7 can be reached using 300 fb-1; this requires 4 jets with ET>40 GeV and |h|<2.5. • For lower integrated luminosity, more tricks are needed and jets down to 20 GeV are preferred. • They concluded trigger rates probably prohibitive. FTK Physics Case Meeting
Signal sample • Match jets to b quarks • Assume b tag req’d using FTK tracks at LVL2 • So set thresholds based on kinematics of b jets. • Bottom right plot is pt of 4th-highest jet matched to b quark. If <4 jets matched, fill a 0. • How would you set thresholds? FTK Physics Case Meeting
Signal sample • Without matching: still j4 has low pT. • No “zeros” in plot. • Consider multiple trigger thresholds. FTK Physics Case Meeting
SHERPA event generator • Recall: two problems w/ SHERPA multijets: • Don’t see much difference btw 22 and 22 + 23, etc. • Matching cut too high? • How to set scale of events, since kinematic cuts can bias distributions? • No solution yet, similar problem with ALPGEN. • SHERPA, please generate: • jet jet -> jet jet • jet jet -> jet jet jet • jet jet -> jet jet jet jet • ME/PS matching at 25 GeV. • Add’l cuts bias kinematicsthrough interaction withmatching scale. • Thus matching also setsscale of interactionby defining “jet”. FTK Physics Case Meeting
Sample L1 rates from SHERPA • Caveats: 22 only; uncertain uncertainties. • Implies very low generation threshold needed for 4j@40. FTK Physics Case Meeting
Next Steps • Generate large sample of SHERPA multijets over holidays. • Some fraction full simulation? • Input from other analyses ASAP to determine parameters of generation. • Reproduce (at some level) the earlier ATLAS study of Hhhbbbb. FTK Physics Case Meeting