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Tau Trigger Study at L1

Tau Trigger Study at L1. Takashi Mitani , Kohei Yorita Waseda University Soshi Tsuno KEK 06/ April/2013. Introduction. → di-tau Trigger is important for this channel. di-tau Trigger Require two hadronic taus at trigger level.

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Tau Trigger Study at L1

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  1. Tau Trigger Study at L1 Takashi Mitani, KoheiYorita Waseda University SoshiTsuno KEK 06/April/2013

  2. Introduction →di-tau Triggeris important for this channel. • di-tau Trigger • Require two hadronictaus at trigger level. • Trigger rate is very large due to the fake from multi-jet events. →Compared to other decay channel, trigger pT thresholds are high. Too High! • For LHC Run2, it is important to design new tau trigger which reject the multi-jets events and control trigger rate with keeping higgs signal sensitivity. • In this talk, we present the first results of optimization of L1 tau trigger. H→ττ→hadron-hadron analysis have the 2nd largest sensitivity in the H→ττ. σ/σSM<1.24 ( ∫Ldt = 4.6+20.3fb-1, 95% C.L@mH=125GeV) KEK-WASEDA Meeting

  3. Tau TriggerSystem Hadron Calorimter EMCalorimeter Core Region Isolation Region Current di-tau TriggerThreshold • Level1(L1): Hardware Based • Calorimeter Tower: Δη×Δφ 0.1×0.1 • Core : 2×2, Isolation : 4×4-2×2 • Use Cluster ET and Isolation information Focus on Level 1 trigger in this talk. • Level2(L2): Software Based • Use information at RoI region • Energy information: 2 variables Track information: 4 variables • Cut based trigger • EventFilter(EF): • Multivariate analysis trigger(BDT) KEK-WASEDA Meeting

  4. Data Set Tau Objects • L1 trigger objects are dR(<0.2) matched with offline tau objects, which are selected by next slide offline tau object selection. • For QCD background, we don’t require the matching with offline tau. • Samples are 8TeV MC and data. • Signal: ggH, VBFH, WH, ZH (125GeV) • mc12_8TeV.161577.PowHegPythia8_AU2CT10_ggH125_tautauhh.merge.NTUP_TAU.e1217_s1469_s1470_r3542_r3549_p1344.no_trigger.v1/ • mc12_8TeV.161617.PowHegPythia8_AU2CT10_VBFH125_tautauhh.merge.NTUP_TAU.e1217_s1469_s1470_r3542_r3549_p1344.no_trigger.v1/ • mc12_8TeV.161657.Pythia8_AU2CTEQ6L1_WH125_tautauhh.merge.NTUP_TAU.e1217_s1469_s1470_r3542_r3549_p1344.no_trigger.v1/ • mc12_8TeV.161697.Pythia8_AU2CTEQ6L1_ZH125_tautauhh.merge.NTUP_TAU.e1217_s1469_s1470_r3542_r3549_p1344.no_trigger.v1/ … common D3PD data used by had-had analysis group. • QCD Background: Enhanced Bias data • data12_8TeV.00202798.physics_EnhancedBias.merge.NTUP_TAU.r3870_r3871_p1153_p1130/ • Fire unprescaled L1 triggers, i.e., EM3, MU4, TAU5, J18, FJ18, XE25, TE250. KEK-WASEDA Meeting

  5. Event & Objects Selection for Signal, Optimization Point @ L1 Event Selection Based Trigger Tau object • (Sub)Leading pt > 30 (20) GeV • |eta|<2.5 • Two taus pass BDTMediumID • Tau author == 1 or 3 • numTrack == 1 or 3 • EleVetoLoose • MuonVeto • Veto, if leading tau track is in crack region , 1.37<|eta|<1.52 • 2 taus have opposite charge • Same Primary Vertex • EF_tau29Ti_medium1_tau20Ti_medium1 Optimization Point @ L1 • Δη threshold • EM Isolation threshold • ET threshold • Require additional 1jet At least 1 primary vertex with num_Tracks >=4 Event Cleaning (i.e. core Flag, LAr, Tile, jet cleaning) Muon veto Electron veto Require exactly 2 taus KEK-WASEDA Meeting

  6. Estimation of trigger rate at LHC Run2 • →The goal is reducing L1 rate from 43.2kH to ~15kHz using L1 trigger objects. • We refer to the following talk. • https://indico.cern.ch/getFile.py/access?contribId=3&resId=0&materialId=slides&confId=172055 • Plan of LHC • √s = 14(13) TeV and 25(50)ns bunch spacing • Peak luminosity turn up step by step (2015: 1.0×1034, 2019:2-3×1034cm-2s-1) →In this talk, estimate L1 rate assuming √s=14TeV, L=1.0×1034cm-2s-1. • Most L1 rates are driven by multi-jet production. • Can extrapolate by ratio of parton luminosities between √s=8TeV and 14TeV • Not consider pile-up effect in this talk. (e.g. 1 minbias event per crossing.) • ex）Di-tau Trigger @ L=1.0×1034cm-2s-1 KEK-WASEDA Meeting

  7. Cluster ET distribution @ L1 Lead L1 Tau Objects Sublead L1 Tau Objects • If we raise Cluster tau ET threshold, we can reduce QCD jets events. But higgs events are also reduced. • If we raised “only” lead L1 tau ET threshold, it is possible to reduce QCD jets events keeping signal acceptance. KEK-WASEDA Meeting

  8. Requirements at L1 EM Isolation Candidates of L1 trigger objects Accept! 3 GeV Δη(τ1,τ2) Accept! Δη<2.0 EM Isolation Hadronic tau objects are narrow. → Require tighter isolation from 4 to 3GeV Δη(τ1,τ2) In proton-proton collision, higgs is boosted to the beam axis.→ 2 taus are in the same hemisphere with respect to η. Require additional jet at L1 KEK-WASEDA Meeting

  9. Backup

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