1. Tampa - April 19, 2005APS April Meeting – M.Rossi1 DILEPTON TRIGGER for SUSY SEARCHES @ CDF Melisa Rossi - Udine University APS April Meeting Tampa, Florida April 19 th, 2005 OUTLINE Motivation CDF Detector & Trigger DILEPTON trigger  layout - strategy  monitoring - calibration Summary

2. Tampa - April 19, 2005 APS April Meeting – M.Rossi 2 Motivation Multi-lepton signatures  emerging from SUSY channels appealing for many other hep searches  leptons from chain decays relatively low p T (< 20 GeV/c)  very clean particularly powerful @ hadron colliders where QCD background dominates Predicted cross-section SMALL!!  σ(SUSY) ~ pb while σ(pp) ~ 50 mb _

3. Tampa - April 19, 2005 APS April Meeting – M.Rossi 3 CDF Detector & Trigger Multipurpose detector  Good calorimeter and muon coverage Electrons |η| < 3.6 Muons |η| <1.5 (trigger < 0.1 )  Precision tracking (Silicon) Trigger System  3-level architecture to minimize deadtime  path = unique combination of L1,L2,L3 Muon/Electron @ trigger level  Muon = 2D track matched to stub stub = set of hits in muon chamber  Electron = 2D track matched to Em deposition in calorimeter

4. Tampa - April 19, 2005 APS April Meeting – M.Rossi 4 DILEPTON trigger inclusive low p T lepton trigger not feasible, then DILEPTON trigger (electrons and muons)  highly redundant (~20 trigger paths) maximize acceptance (geometry and inefficiency) easier to understand trigger  comparisons between paths  keep calibration and monitoring samples in the same data set extraction of unbiased lepton samples detector conditions naturally folded in

5. Tampa - April 19, 2005 APS April Meeting – M.Rossi 5 DILEPTON trigger strategy CEM4 (4 GeV central electron) CEM8 (8 GeV central electron) PEM8 (8 GeV forward electron) CMU4 (4 GeV muon, η<0.6) CMUP4 (4 GeV muon, η<0.6) CMX4 (4 GeV muon, 0.6<η<1) MUONS ELECTRONS

6. Tampa - April 19, 2005 APS April Meeting – M.Rossi 6 DILEPTON trigger layout A. baseline - workhorse B. to recover stub/cluster inefficiency C. to increase the acceptance ABC L1 L2 2 Low-p T leptons Medium-p T lepton+track High-p T inclusive lepton L3 2 Low-pt leptons 20 trigger paths CEM4_CMU4 CEM4_CMUP4 CEM4_CMX4 CEM4_PEM8................ CEM4_CMU4_L2_CEM8_TRK8....... CEM4_CEM4_L2_CEM12 A A B B C C

7. Tampa - April 19, 2005 APS April Meeting – M.Rossi 7 DILEPTON trigger strategy single lepton types definitions  do not depend on the specific path trigger studies for each lepton type combine single lepton type results into trigger paths 20 trigger paths 6 lepton types Monitoring & Calibration for each lepton type Monitoring & Calibration for each lepton type CEM4 CEM8 PEM8 CMU4 CMUP4 CMX4

8. Tampa - April 19, 2005 APS April Meeting – M.Rossi 8 Monitoring Stability defining a suitable variable  sort of purity (event quality information)  expected to be stable in time  provides information for each lepton type  different estimations for each lepton type provide cross checks between paths CEM4 e.g. track direction used to calculate E T (instead of cluster) steps in distributions indicatives of trigger changes

9. Tampa - April 19, 2005 APS April Meeting – M.Rossi 9 Calibration: L1 Electron Primitives Trigger requirements L1 4 GeV Central electron  Trigger Tower E T ≥ 4 GeV E had /E em ≤ 12.5%  Track P T ≥ 4 GeV/c L1 8 GeV Forward Electron  Trigger Tower E T ≥ 8 GeV E had /E em ≥ 6.25% em

10. Tampa - April 19, 2005 APS April Meeting – M.Rossi 10 Calibration: Probe Electrons Must satisfy ID cuts Must be unbiased for the trigger being calibrated i.e. events collected by triggers unrelated to the one tested Must come from a conversion  each electron associated with a track requiring |Δcotθ|<0.15, S xy <0.1  Consider 2 sub-samples Peak |Δcotθ|<0.03 (Electrons+Fakes) Sideband |Δcotθ|>0.05 (assuming Fakes only)

11. Tampa - April 19, 2005 APS April Meeting – M.Rossi 11 Calibration: L1 Trigger Efficiency Forward electron efficiency slow turn-on due to online-offline energy difference Central electron efficiency plateau value ~ 90% due to tight track requirement CENTRALFORWARD

12. Tampa - April 19, 2005 APS April Meeting – M.Rossi 12 Summary Motivation  Targeting processes yielding to multiple leptons in final states DILEPTON trigger @ CDF  redundant multipath trigger structure  fully efficient beyond 4 GeV Strategy  use single lepton type definition  simplify monitoring and calibration of multipath trigger !!  re-combine single lepton results into trigger paths Calibration is on-going

13. Tampa - April 19, 2005 APS April Meeting – M.Rossi 13 Back-up TRIGGER PATH LIST 1. cem4_cmu4 2. cem4_cmu4_l2_cem8_pt8_ces2_&_trk8 3. cem4_cmu4_l2_trk8_l1_cmup6_pt4 4. cem4_cmup4 5. cem4_cmx4 6. cem4_cmx4_l2_cem8_pt8_ces2_&_trk8 7. cem4_pem8 8. cem4_pem8_l2_cem12_pt8 9. cem8_pem8 10. cmu4_pem8 _ 11. cmu4_pem8_l2_trk8_l1_cmup6_pt4 12. cmup4_pem8 13. cmx4_pem8 14. dielectron_central_4 15. dielectron_central_4_l2_cem12_pt8 16. dielectron_central_4_l2_cem8_pt8_ces2_&_trk8 17. dimuon_cmu4_cmx4 18. dimuon_cmu4_cmx4_l2_trk8_l1_cmup6_pt4 19. dimuon_cmucmu4 20. dimuon_cmucmu4_l2_trk8_l1_cmup6_pt4 21. dimuon_cmup4_cmx4 22. dimuon_cmupcmup4 1. cem4_cmu4 2. cem4_cmu4_l2_cem8_pt8_ces2_&_trk8 3. cem4_cmu4_l2_trk8_l1_cmup6_pt4 4. cem4_cmup4 5. cem4_cmx4 6. cem4_cmx4_l2_cem8_pt8_ces2_&_trk8 7. cem4_pem8 8. cem4_pem8_l2_cem12_pt8 9. cem8_pem8 10. cmu4_pem8 _ 11. cmu4_pem8_l2_trk8_l1_cmup6_pt4 12. cmup4_pem8 13. cmx4_pem8 14. dielectron_central_4 15. dielectron_central_4_l2_cem12_pt8 16. dielectron_central_4_l2_cem8_pt8_ces2_&_trk8 17. dimuon_cmu4_cmx4 18. dimuon_cmu4_cmx4_l2_trk8_l1_cmup6_pt4 19. dimuon_cmucmu4 20. dimuon_cmucmu4_l2_trk8_l1_cmup6_pt4 21. dimuon_cmup4_cmx4 22. dimuon_cmupcmup4

14. Tampa - April 19, 2005 APS April Meeting – M.Rossi 14 Back-up Plug Conversion Selection