1. M. Pilar Casado 1 Optimization of Tau Menus: L1 & L2 Trigger & Physics week (19-22 March 2007) M. Pilar Casado (IFAE & UAB) on behalf of the Tau Trigger Group

2. M. Pilar Casado 2 Outline Introduction LVL1 cluster LVL1 calibration Study on LVL1 EM & Had Isolation L2 optimization Summary and outlook

3. M. Pilar Casado 3 Introduction misal1_csc11.005009.J0_pythia_jetjet.digit.RDO.v12003103 (8 GeV < pT < 17 GeV) 134000 events. Cross section = 17.40 mbarns. misal1_csc11.005010.J1_pythia_jetjet.digit.RDO.v12003103 (17 GeV < pT < 35 GeV) 99600 events. Cross section = 1.38 mbarns. misal1_csc11.005011.J2_pythia_jetjet.recon.AOD.v12000502 (35 GeV < pT < 70 GeV) 9000 events. Cross section = 9.33x10 -2 mbarns. misal1_csc11.005012.J3_pythia_jetjet.digit.RDO.v12003101 (70 GeV < pT < 140 GeV) 6150 events. Cross section = 5.88x10 -3 mbarns. trig1_misal1_csc11.005107.pythia_Wtauhad.recon.AOD.v12000501 (W → tau nu) 8400 events. trig1_misal1_csc11.005188.A3_Ztautau_filter.recon.AOD.v12000501 (Z → tau tau) 16500 events.

4. M. Pilar Casado 4 LVL1 definitions –TauClus: Energy in 2x1 EM + 2x2 Had. -EmIsol: Energy between 2x2 and 4x4 (EM). -HdIsol: Energy between 2x2 and 4x4 (Had). -EmCore: Energy in 2x2 EM + 2x2 Had. -E4X4: Energy in 4x4 EM+Had. Standard LVL1 cluster

5. M. Pilar Casado 5 Study of tau cluster Different tau clusters for a rate of 2 kHz. Steeper curve for E4x4.

6. M. Pilar Casado 6 Study of tau cluster MC true norm. Norm. Offline tau (No cut on pTVis) (Include offline MET>40 GeV) Cut on TauClus 13 GeV -> Rate: 2 kHz, Eff: 55%, 77 (85)% Cut on E4X4 13 GeV -> Rate: 5 kHz, Eff: 70%, 90 (94)% Cut on E4x4 20 GeV -> Rate: 2 kHz, Eff: 43%, 62 (75)% Cut on E4x4 13 GeV + MET16 -> Rate: 2 kHz, Eff: 55%, 69 (92)% Specific study for W → tau nu. Conclusion on the study of the tau cluster: For the same rate the use of E4X4 with Missing ET gives somewhat better rates than TauClus standalone. TAU15

7. M. Pilar Casado 7 Study LVL1 calibration for TauClus (1) Determine hadronic weights which minimize RMS for different eta intervals. 0.3-0.6 -> Min ~ 1.1 1.1-1.4 -> Min ~ 1. 2.0-2.5 -> Min ~ 1. 0.0-0.3 -> Min ~ 1.1 0.6-1.1 -> Min ~ 1.1 1.4-2.0 -> Min ~ 0.9

8. M. Pilar Casado 8 Study LVL1 calibration for TauClus (2) Check resolution with standard and optimal weights. - RMS improves by 3 - 6 %.

9. M. Pilar Casado 9 Study LVL1 calibration for TauClus (3) Check the effect of the weights in the efficiency as a function of Vis PT and eta. - The efficiency improves by ~3 %. TAU25i, W → 

10. M. Pilar Casado 10 Study LVL1 calibration for TauClus (4) Check the effect of the weights in the rates.. Conclusion: An adjustment of the calibration results in a slight increase of the efficiency for the signal and more uniformity across eta. The total background is unchanged but is also more uniform across eta. TAU25i

11. M. Pilar Casado 11 Em Isolation Rate -20%, Efficiency -5% For EmIsol < 5: Rate -15%, Efficiency -5% Rate -40%, Efficiency -5% More efficient at high energy

12. M. Pilar Casado 12 Had Isolation Rate -20%, Efficiency -10% For HdIsol < 3: Rate -10%, Efficiency -10% Rate -40%, Efficiency -10% Not as efficient as EmIsol

13. M. Pilar Casado 13 An example of LVL 2 calorimeter optimization Tau15iTau25iTau35i EMRadius0.0127 0.0086 0.0127 0.0068 0.0127 0.0059 isoFrac0.55 0.41 0.55 0.35 0.55 0.32 stripWidth20.055 0.061 0.055 0.052 0.055 0.046 Energy11.0 16.5 20.0 24.5 23.3 31.4 W→  signal Efficiency 95% 85% -10% 95% 85% -10% 97% 85% -10% Background rate (10 31 ) 775 Hz 566 Hz -30% 146 Hz 116 Hz -30% 40 Hz 29 Hz -30% EMRadius Strip Width M. Bosman, E. Pérez

14. M. Pilar Casado 14 Ongoing LVL2 optimization List of issues to be addressed in the near future: –Calorimeter (T2CaloTau): optimization of cuts & cluster seed definition optimize tau LVL2 calorimeter calibration. –Tracking (T2IDTau): optimization of cuts for each menu investigation of pt-balance or candidate mass cut –“EFlow” à la tau1P3P (algorithm exists, needs testing). simpler approach. M. Bosman, O. Igonkina, E. Pérez

15. M. Pilar Casado 15 Technical status Migration to new steering and new python configuration is completed. L2 runs in nightly and gives output simular to 12.0.6. EF is under tests Migration to configurables has not progressed very far due to delays with ToolHandleArray and due to delays of migration of offline code (not only tauRec, but also cluster and track reconstruction) All algorithms are migrated to new way of monitoring/validation as will be described by Meng O. Igonkina, S. Xella

16. M. Pilar Casado 16 Summary and outlook For the study of the LVL1 tau cluster: For the same rate the use E4X4 with Missing ET gives somewhat better rates than TauClus standalone (normalizing with respect to offline and using offline MET). For the study on the LVL1 calibration: An adjustment of the calibration results in a slight increase of the efficiency for the signal and more uniformity across eta. The total background is unchanged but is also more uniform across eta. From LVL2: many ongoing optimizations that will help in the overall performance. Documentation on Tau Hypothesis algorithms (including cuts for 12.0.6): https://twiki.cern.ch/twiki/bin/view/Atlas/TauPESA#Trigger_Hypothesis_algorithms For the future: –Include new LVL1 calibration when available. –Extend studies to 10 33 and 900 GeV. –Continue LVL2 optimization.