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L2 Tau Trigger Review

M.Bachtis. L2 Tau Trigger Review. Motivation. Upgrade the clustering algorithm Test on High pt samples Apply Relaxing cuts Samples Z->tautau Full Simulation(10K) ‏ qqH(135)->tautau Full Simulation(25K) ‏ H(200)+->tau nu Full Simulation (10K) ‏ QCD (40 Million) – Fast Simulation

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L2 Tau Trigger Review

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  1. M.Bachtis L2 Tau Trigger Review

  2. Motivation Upgrade the clustering algorithm Test on High pt samples Apply Relaxing cuts Samples Z->tautau Full Simulation(10K)‏ qqH(135)->tautau Full Simulation(25K)‏ H(200)+->tau nu Full Simulation (10K)‏ QCD (40 Million) – Fast Simulation L1 decision For ZTT and QQH we look at L1_DoubleTau_40 For HCH we look at L1_SingleTau35_L1MET30 For QCD we look both (two different outputs)

  3. Available Cuts ECAL Isolation Sum Et in annulus (0.15-0.5) around jet axis Sum Et in annulus (0.15,0.5) around ecal mean Et pos Number of clusters in annulus (0.2-0.5) around jet Number of clusters in annulus (0.2-0.5) around ecal mean Et pos Cluster eta/phi/dr RMS around jet axis Cluster eta/phi/dr RMS around ecal weighted axis Tower Isolation Sum of tower et in annulus(0.5,0.5) around jet axis

  4. Jet Et Z ->tautau H ->tautau QCD Di-Jet QCD DiJet H ->tautau QCD Jet 15 GeV is the L2 reconstruction cut on Jet Et.

  5. Jet Structure 9% of the Matched jets has No ECAL! 8% has No HCAL! Intercations in tracker/ECAL(?)‏ QCD more equally weighted More pi0s for higher tau energy The No ECAL jets populate all the Et spectrum Z ->tautau QCD Di-Jet Z ->tautau

  6. ECAL /Tower Isolation Et Z ->tautau Z ->tautau QCD-DiJet QCD DiJet ECAL isolation similar to any axis (HCAL noise might change that) Z ->tautau QCD DiJet

  7. Clustering Z ->tautau Z ->tautau QCD-DiJet QCD-DiJet Z ->tautau Z ->tautau QCD-DiJet QCD-DiJet

  8. Optimization strategy PF narrower than MC Optimize vs MC QQH consistent with ZTT H->tau nu:more occupied events ZTT(MC)‏ QCD(MC+PF)‏ Z->tautau Z->tautau H+->tau nu H->tautau

  9. Tails of the distributions Z->tautau QCD Di_Jet Tails tend to move forward lower Et

  10. Cut comparison: ref to MC ROC Curves ECAL Isol Et ECAL Isol EtW # Clusters H->tautau (MCMatch)‏ Cluster eta RMS Cluster phi RMS Cluster dr RMS Tower Isol. Et -Cut performance changes at 90% -Errors to small -Number of Clusters :same performance to ECAL Isol Et >90% -Cluster dr RMS->Very powerful for Eff<90%

  11. Efficiency vs Et cut by cut H->tautau (MCMatch)‏ ECAL Isol Et<5(Flat)‏ # Clusters<4(Flat)‏ Dr RMS<0.025(Goes up with Et)‏ Tower Isol. Et<7(Goes down with Et)‏

  12. Sliding cuts motivation Currently the only cut applied is ECAL isol Et< 5GeV (96% H->tautau,60% QCD Di Jet)‏ Flat vs Et (Good cut)‏ But We reject events on the full Et Spectrum Over 100GeV the rate is reduced enough so that we can reduce bias by accepting more events there So we could create a gradually relaxing cut with Et We can tune the cuts to keep efficiency and QCD rejection the same if not slightly better but by accepting more higher Pt candidates

  13. Sliding Cut with # clusters in annulus (0.2-0.5)‏ • Compare • N clusters< 2.5+0.01Et+0.0005Et2 • N clusters<2+0.01Et+0.0005Et2 • EcalIsol Et <5 (standard)‏ H->tautau(MC)‏ H->tautau Efficiency(MC) = (98%,97%,97%)‏ H->tautau Efficiency(PF)= (~99%)‏ QCD Efficiency = (58%,52%,58%)‏ Same or less background H->tautau(MC/PF)‏ Reject more in High QCD rate region. Accept more in low QCD rate region QCD Di-Jet

  14. Efficiency per sample(ref to MC)‏ Cut Sample Efficiency Standard Z->tautau 96% Standard H->tautau 97% Standard H->taunu 92% 59% Standard QCD DiJet Standard QCD Jet 59% Sliding Z->tautau 94%/97% Sliding H->tautau 97%/98% Sliding H->taunu 96%/97% Sliding 51%/58% QCD DiJet Sliding 52%/58% QCD Jet

  15. Summary Depending on the required signal efficiency different cut combinations can be used Sliding cuts can improve data quality without significant rate increase N clusters in annulus is a good cut to use Follows PF Egamma Isolation Expected to be more robust to pile up

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