1. Efficiency of the L1 Trigger for SUSY Study performed by L. Boldizsár, P. Hidas KFKI Budapest J. Erö, M. Fierro, A. Jeitler, N. Neumeister, P. Porth, H. Rohringer, L. Rurua, H. Sakulin, A. Taurok, C.-E. Wulz HEPHY Vienna presented by Claudia-Elisabeth Wulz CPT Week, CERN, 8 May 2003

2. CPT Week, May 2003 C.-E. Wulz2 Tridas Scenario and Physics Channels Luminosity: 2x10 33 cm -2 s -1 Tridas scenario: 50 kHz Level-1 trigger rate (16 kHz with safety factor) 8 physics channels studied (A-H) -A: Smuons at Snowmass point 1a -  L  L with  L ->    -B: Charginos/neutralinos at Snowmass point 1a -       - with    ->      and    ->     ;    ->      ;    -> e  -C: Gluinos/squarks Snowmass point 1a - D: Gluinos/squarks Snowmass point 2 -E: Sparticles JetMet mSUGRA4 -F: Sparticles JetMet mSUGRA5 -G: Sparticles JetMet mSUGRA6 -H: WW with W ->  (benchmark channel) ~~~ ~ ~~ ~ ~ ~ ~ ~~

3. CPT Week, May 2003 C.-E. Wulz3 Parameter Choice Snowmass point 1a Snowmass point 2 tan  = 10, sgn(  ) =  A 0 =  100 GeV (A,B,C) A 0 =  GeV (E,F,G)

4. CPT Week, May 2003 C.-E. Wulz4 mSUGRA Jet and Missing E T distributions

5. CPT Week, May 2003 C.-E. Wulz5 Monte Carlo Input A, B, C, D, H: PYTHIA 6.158 E, F, G: ISAJET 7.51 Parton distribution functions CTEQ5L used for all channels. 1000 events for SUSY channels, 2000 events for WW channel. On average 3.5 minimum bias events produced with PYTHIA 6.158 added.

6. CPT Week, May 2003 C.-E. Wulz6 Detector and Trigger Simulation CMSIM 125 used for hit simulation, separately for signal and pile-up. Digis produced with ORCA 6, mixing signal plus in-time pile-up. Out-of-time pile-up simulated by superposing bunch crossings -5, …, +3. HCAL non-linearity correction applied. Intrinsic RPC noise not added due to CPU time constraints. Level-1 performance simulated in ORCA. Bit-wise arithmetic used wherever possible. Results are given at the end of the Level-1 chain, i.e. at the output of the Global Trigger.

7. CPT Week, May 2003 C.-E. Wulz7 Trigger Menu Thresholds chosen to yield total rate of 16 kHz, which are allocated to physics triggers at Level-1. Muon thresholds are from the DAQ/HLT TDR. Bandwidth quota is divided into four roughly equal groups:  /  e /ee  /  Jets, E T sums and combinations Total rate is smaller than sum of rates for 4 groups due to overlaps. 3.6 kHz } 4.3 kHz 3.0 kHz } 3.6 kHz } }

8. CPT Week, May 2003 C.-E. Wulz8 Efficiencies Nr. of events generated (no geometrical restrictions) Efficiency = Nr. of events passing L1 trigger in its fiducial volume Individual efficiency: eff. of a trigger as if it were the only trigger applied In practice: triggers overlap Additional efficiency: events found by previous trigger not counted (order of trigger conditions relevant) Exclusive efficiency: eff. for events found by one and only one trigger

9. CPT Week, May 2003 C.-E. Wulz9 Efficiencies A-D, H (WW)

10. CPT Week, May 2003 C.-E. Wulz10 Efficiencies E, F, G (mSUGRA) Efficiencies at the upper mass reach of Tevatron Run II

11. CPT Week, May 2003 C.-E. Wulz11 Total Efficiencies Channel Total efficiency A 93.4 % B 72.3 % C 97.9 % D 100.0 % E 96.2 % F 96.3 % G 88.9 % H 81.3 %  Chargino/neutralino channel has lowest efficiency.

12. CPT Week, May 2003 C.-E. Wulz12       : generated E T vs  of highest-E T electron  E T is either low or electrons are outside trigger acceptance ~~

13. CPT Week, May 2003 C.-E. Wulz13       : generated E T and E of invisible particles Can trigger on missing E T help? ~~ Invisible E T about the same for accepted and rejected events, whilst E is higher for rejected than accepted events! Rejected events tend to balance their contributions in E T. Probability for cancellation high due to many invisible particles.

14. CPT Week, May 2003 C.-E. Wulz14 Effects of thresholds, resolution, acceptance For a qualitative appreciation of the different effects the  and  trigger efficiencies were studied for smuons (A) (   = 92.5%,   = 68.8%) and gluinos/squarks (C) (   = 27.8%,   = 13.8%). Generated p T of 2 highest-p T muons Smuons Squarks/gluinos

15. CPT Week, May 2003 C.-E. Wulz15 p T of Level-1 Muon Candidates Level-1 p T of 2 top muons SmuonsSquarks/gluinos Single-muon threshold

16. CPT Week, May 2003 C.-E. Wulz16  of Generated and Level-1 Muons Generated  of 2 highest-p T muons Smuons Squarks/gluinos  trigger acceptance boundary Level-1  of 2 top muons

17. CPT Week, May 2003 C.-E. Wulz17 Conclusions Level-1 trigger efficiencies for 7 SUSY channels and WW studied for the initial low luminosity LHC run with scenario of 50 kHz maximum Level-1 trigger rate  Most efficiencies are good, over 90%  Lower efficiency for charginos/neutralinos comes mainly from physics