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H FTK update Catalin, Tony FTK meeting, 9/7/2006
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Recap: H with FTK Step1: look at LVL1 side Step2: look at LVL2 side Similar to Kohei’s study LVL1 (+new trigger) LVL2 (+FTK) 40 kHz 200 Hz
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Recap: EM and tau at LVL1 Had sum<2 GeV EM isolation<4 GeV electron tau Definition of EM: –L1Em_EmClus > threshold && –L1EmIsol < 4 GeV && –L1Em_HdIsol+L1Em_HdCore < 2 GeV Definition of : –L1Em_TauClus > threshold && –L1EmIsol < 4 GeV && –L1Em_HdIsol < 2 GeV
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LVL1 EM and tau dijet rates Eric and Alan pointed us to the latest dijet study by Pilar Casado (IFAE, Barcelona): –https://twiki.cern.ch/twiki/bin/view/Atlas/LVL1TauStudieshttps://twiki.cern.ch/twiki/bin/view/Atlas/LVL1TauStudies –LVL1 trigger rates are given for 10^31 for various thresholds –L1em_EmClus>9GeV && L1EmIsol<4GeV: 1.6 kHz (we: 1.4kHz) –L1em_TauClus>9GeV && L1EmIsol<4GeV: 2.8 kHz (we: 2.3kHz) –Different cross-sections could account for this 13% and 18% diff. –Only J1 and J2 samples contribute significantly to the rates: EM trig: J1,J2,J3,(J4+…+J8) ~ 81%, 18%, 1%, <0.06% TAU trig: J1,J2,J3,(J4+…+J8) ~ 83%, 16%, 1%, <0.05%
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LVL1 trigger study According to Alan Watson : –LVL1 trigger decision based on multiplicities alone (does not use any roi info at LVL1) Run over dijet and keep track of the following: –Isolated EM cluster count: EM –Isolated TAU cluster count (could be the same as above): EM-had –Isolated TAU cluster different from EM count: !EM –( EM-had, EM-had ) pair count –( !EM, !EM ) pair count –(EM+ 2 EM-had ) count –(EM+ 1 !EM ) count
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LVL1 Trigger Rates at 2*10 33 cm -2 s -1 1EM (black) up to 300 kHz 1 EM-had (red) up to 150 kHz LVL1 projected 40 kHz, designed max output 75 kHz
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EM+ LVL1 trigger rate at 2*10 33 EM+>1 EM-had rate up to 10 kHz –Shown versus EM-threshold or threshold –Stronger dependence on threshold than on EM threshold
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2 LVL1 trigger rate at 2*10 33 Require 2 EM-had objects Rate up to 20 kHz
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2 !EM LVL1 trigger rate at 2*10 33 Not possible to trigger on, but interesting As much as 3kHz comes from 2 hadronic taus Could be interesting to study if and how much increases signal acceptance in the all-had channel
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Step2 – LVL2 rejection Thanks to Paola for pointing us to the CMS algorithm RORO RIRI RSRS leading P T track Recipe: - find leading P T track in a R I =0.1 cone around the jet - require P T (lead. track) > 3 GeV - find tracks within an R S =0.07 cone around lead. - count, as before, tracks in the isolation reg: R S <R<R O Jet axis
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3,1 2,2 2,1 4,0 3,0 1,2 1,1 2,0 1,0 Max tracks in,out “in” tracks are here w/ P t >1.0 “out” tracks are here w/ P t >0.5 factor of ~1.4 optimum R O =0.3, P T Sig >3.0 GeV/c R O =0.5, P T Sig >10.0 GeV/c Curves correspond to different R O & min leading P T. R S =0.07, R I =0.1 for all. Higgs 130 GeV
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3,1 2,2 2,1 4,0 3,0 1,2 1,1 2,0 1,0 Max tracks in,out factor of ~10 R O =0.3, P T Sig >3.0 GeV/c R O =0.5, P T Sig >10.0 GeV/c Curves correspond to different R O & min leading P T. R S =0.07, R I =0.1 for all. “in” tracks are here w/ P t >1.0 “out” tracks are here w/ P t >0.5 Sherpa Dijet
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Conclusions and Outlook We believe we have the correct LVL1 trigger implementation, and we verified that we can reproduce some recent dijet trigger rates to within 10-20% At LVL2 we can dial dijet rejections corresp to factors of 5-100. Questions are: –How much is it admissible to increase the LVL1 or LVL2 output rates? –Which of the above limits us? For example, we can add EM+tau trigger with thresholds 10-25 GeV which would increase the LVL1 output rate by <10 kHz Remains to be investigated: –How much signal we gain –If we would gain significantly in the hadronic ditau Higgs channel
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Recap: Trigger Study – May 06 0 1 2 3 4 5 6 LOW-LUMHIGH-LUM MU20(20) 2MU6 EM25I(30) 2EM15I(20) J200(290) 3J90(130) 4J65(90) J60+xE60(100+100) TAU25+xE30(60+60) MU10+EM15I Lepton E T Tau E T Missing E T 15,20,25,30 10,15,20,25 10,15,20
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Recap: Low Luminosity Regime Signal: 130 GeV H E T ( ) threshold E T (lep) > 10 GeV E T ( ) threshold E T (lep) > 15 GeV E T ( ) threshold E T (lep) > 20 GeV met>15 met>30 Reminder: - only lepton, tau, and met thresholds are varied - rest of the trigger table stays the same Biggest effect: lowering the lepton E T threshold (up to 15% gain) Trigger efficiency
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More Backup 1 !EM rates vs EM or thresholds (at L=2*10 33 ) Stronger dependence on threshold
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