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SUSY Triggers at CMS

SUSY Triggers at CMS. Salavat Abdullin For CMS Collaboration. SUSY 2005, July 18-23, 2005 Durham, UK. Outline. LHC rate challenge. mSUGRA test points. L1 trigger. L2 inclusive jet + E T miss. L2 trigger cuts optimization. More (cross-) triggers. QCD multi-jet rate. Summary.

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SUSY Triggers at CMS

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  1. SUSY Triggers at CMS Salavat Abdullin For CMS Collaboration SUSY 2005, July 18-23, 2005 Durham, UK S.Abdullin SUSY Triggers

  2. Outline LHC rate challenge mSUGRA test points L1 trigger L2 inclusive jet + ETmiss L2 trigger cuts optimization More (cross-) triggers QCD multi-jet rate Summary S.Abdullin SUSY Triggers

  3. Triggering on SUSY : Rate Challenge Task : reduce 40 MHz bx rate ( ~1 GHz pp) O(100 Hz) To preserve maximal SUSY signal efficiency in jets + ET channel Inclusive Jet Rate (cone algorithm, R=0.5) Expected Missing ET Rate Recon. MET (hi lumi)Recon. MET (low lumi)Gen. MET (hi lumi)Gen MET (low lumi) Full GEANT-based CMS simulation + OO reconstruction CMS DAQ TDR CERN/LHCC 2002-26 High lumi Calo resolution Low lumi Requiring a rate to tape of a ~few Hz implies an inclusive single-jet threshold of 350-500 GeV and an inclusive missing ET threshold of 100-170 GeV S.Abdullin SUSY Triggers

  4. SUSY Points • mSUGRA low-mass test • points (“4-6”) have been • chosen fo DAQ TDR: • -close to the Tevatron reach • different final state • topologies • (backup slides contain • more details) DAQ TDR points mSUGRA high-mass points (“7-9”) from DAQ TDR are not considered here as having fairly high trigger efficiency “LM” and “HM” points (low and high mass) for Phys. TDR DAQ TDR points http://cmsdoc.cern.ch/cms/PRS/susybsm/msugra_testpts/msugra_testpts.html S.Abdullin SUSY Triggers

  5. L1 SUSY Triggers L1 Jet&MET triggers alone are > 80 % efficient, SUSY signal efficiency (%) and background rate (kHz) Differ from DAQ TDR numbers as not 95% cuts 96.2% 96.3% 88.9% All L1 triggers ~ 89-96% CMS Note 2003/028 S.Abdullin SUSY Triggers

  6. Inclusive SUSY Jet+MET mSUGRA 5 L2 Efficiency Running a bit ahead – chosen L2 cuts yield ~ 45-65 % efficiency at a few Hz of QCD rate QCD L2 rate (Hz) Jet1 threshold (150 GeV) - calibrated MET threshold (92 GeV) - raw 2 1 -1 S.Abdullin SUSY Triggers

  7. Chosen L2 Triggers (I) L2 triggers : a combination of J1+MET and J4 J1+MET works for “standard” SUSY, while J4 - for most challenging (fot trigger) R-parity violation scenario 3j, points 4R, 5R, 6R ~ c 0 1 J4 MET, J1 fixed @ 150 GeV S.Abdullin SUSY Triggers

  8. Chosen L2 Triggers (II) Cuts were optimized simultaneously for all 6 probing SUSY points using Genetic Algorithm for given rate allocation of ~ 12 Hz (more details can be found on the backup slides) SUSY signal efficiency (%) and background rate (Hz) 180 & 123 GeV at 95% eff in DAQ TDR 113 GeV at 95% eff In DAQ TDR mostly QCD S.Abdullin SUSY Triggers

  9. More Triggers For SUSY Lepton + MET - SM bkgd. : normalize predictions for W and tt - might add smth. to SUSY signal, especially if c decay leptonically - MET+lepton+jet might be too complicated, so - lepton + MET (above) - jet + MET (exists) - lepton + jet (1/2 exists, for electrons) 2leptons + MET might help to keep low thresholds and low rates The efficiencies of these triggers (above) for SUSY have to be studied for CMS Physics TDR S.Abdullin SUSY Triggers

  10. L1-L2 Streams For SUSY Among various possible combinations of L1 and L2 triggers there are typically just a few “leading” streams which provide the essential part of the signal efficiency For instance, among 18 L1-L2 streams considered, only 6 are essential both for R-parity conservation and violation scenarios. S.Abdullin SUSY Triggers

  11. QCD Multijet Rate Issue All previous rate calculations have been made with PYTHIA (shower model) QCD multi-jet is a main rate component, about 90% of the total rate even at L2, so since years there was a question about possible significant underestimate of the QCD rate Now a preliminary comparison of the inclusive jet ET distributions is made at the level of the MC jets between ALPGEN 2.01 and PYTHIA 6.2 (“old” shower model) Details of calculation can be found on the backup slides S.Abdullin SUSY Triggers

  12. Inclusive Jet ET Distributions For low-Et and “medium”-Et 3d and 4th jets the difference does not look significant Harder jet ET cuts to be investigated ! S.Abdullin SUSY Triggers

  13. Summary No problem with L1 trigger even for low-mass SUSY L2 has to be optimized due to the limited bandwidth allocated to jets and MET More cross-triggers might possibly increase L2 SUSY signal efficiency (to be studied) Preliminary comparison of 3d and 4th jets inclusive distributions show a good Agreement between ALPGEN and PYTHIA S.Abdullin SUSY Triggers

  14. Backup Slides S.Abdullin SUSY Triggers

  15. DAQ TDR mSUGRA Test Points Tevatron mass reach S.Abdullin SUSY Triggers

  16. R-Parity Violation Scenario S.Abdullin SUSY Triggers

  17. Probing Points with R-Parity S.Abdullin SUSY Triggers

  18. L2 MET Distributions _ Similar to t t S.Abdullin SUSY Triggers

  19. Number of L2 Jets S.Abdullin SUSY Triggers

  20. Leading L2 Jets S.Abdullin SUSY Triggers

  21. Hybrid Genetic Algorithm (I) S.Abdullin SUSY Triggers

  22. Hybrid Genetic Algorithm (II) S.Abdullin SUSY Triggers

  23. Hybrid Genetic Algorithm (III) S.Abdullin SUSY Triggers

  24. QCD Simulation with PYTHIA Official CMS Production data cards ^ PT > 20 and 120 GeV To put ALPGEN and PYTHIA data on the common ground a cut of 120 GeV is applied on the 1st jet ET in both samples S.Abdullin SUSY Triggers

  25. ALPGEN samples ALPGEN v201 Q2= PT2(parton) PDFs CTEQ5L Matching scheme CKKW (M Mangano impementation in Alpgen, see http://mlm.home.cern.ch/mlm/alpgen) Jet parameters for matching: ET(jet) > 15 GeV R(jet) = 0.525, R(parton-jet) < 0.7875 S.Abdullin SUSY Triggers

  26. ALPGEN samples 2-to-2 : Npartons=2; PT(parton)>20 (100) GeV; |eta|<5 R(parton-parton) >0.7 2-to-3 : Npartons=3; PT(parton)>20 (100) GeV; |eta|<5 R(parton-parton) >0.7 2-to-4 : Npartons=4; PT(parton)>20 (100) GeV; |eta|<5 R(parton-parton) >0.7 (parton= outgoing parton) S.Abdullin SUSY Triggers

  27. sample (matched-alp)(unw-alp) matching (pythia) 2-2 0.4 mb 0.8 mb 0.5 - 2-3 0.02 mb 0.06 mb 0.3 - 2-4 0.0024 mb 0.016 mb 0.15 - total 0.45 mb 0.876 mb - 0.83 mb sample (matched-alp)(unw-alp) matching (pythia) 2-2 6 × 10-4 mb 0.0013 mb 0.45 - 2-3 1.5 × 10-5 mb 4 × 10-5 mb 0.38 - 2-4 1 × 10-6 mb 3.6 × 10-6 mb 0.27 - total 6.16 ×10-4 mb 1. 344 × 10-3 mb - 6.3×10-4 mb samples cross sections 20 GeV 100 GeV S.Abdullin SUSY Triggers

  28. Pseudorapidity distributions 3d jet ET > 100 GeV, 4th jet ET > 100 GeV S.Abdullin SUSY Triggers

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