July 20, 2005S.Abdullin SUSY Triggers1 Salavat Abdullin For CMS Collaboration SUSY 2005, July 18-23, 2005 Durham, UK

July 20, 2005S.Abdullin SUSY Triggers2 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

July 20, 2005S.Abdullin SUSY Triggers3 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 + E T channel Recon. MET (hi lumi) Recon. MET (low lumi) Gen. MET (hi lumi) Gen MET (low lumi) Expected Missing E T Rate Calo resolution Requiring a rate to tape of a ~few Hz implies an inclusive single-jet threshold of GeV and an inclusive missing ET threshold of GeV Low lumi High lumi Inclusive Jet Rate (cone algorithm, R=0.5) Full GEANT-based CMS simulation + OO reconstruction CMS DAQ TDR CERN/LHCC

July 20, 2005S.Abdullin SUSY Triggers4 SUSY Points DAQ TDR 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) mSUGRA high-mass points (“7-9”) from DAQ TDR are not considered here as having fairly high trigger efficiency DAQ TDR points “LM” and “HM” points (low and high mass) for Phys. TDR

July 20, 2005S.Abdullin SUSY Triggers5 L1 SUSY Triggers L1 Jet&MET triggers alone are > 80 % efficient, All L1 triggers ~ 89-96% CMS Note 2003/028 SUSY signal efficiency (%) and background rate (kHz) Differ from DAQ TDR numbers as not 95% cuts 96.2% 96.3% 88.9%

July 20, 2005S.Abdullin SUSY Triggers6 Inclusive SUSY Jet+MET 1 2 QCD L2 rate (Hz) mSUGRA 5 L2 Efficiency Running a bit ahead – chosen L2 cuts yield ~ % efficiency at a few Hz of QCD rate Jet1 threshold (150 GeV) - calibrated MET threshold (92 GeV) - raw

July 20, 2005S.Abdullin SUSY Triggers7 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 J4 MET, J1 150 GeV    

July 20, 2005S.Abdullin SUSY Triggers8 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) mostly QCD 113 GeV at 95% eff In DAQ TDR 180 & 123 GeV at 95% eff in DAQ TDR

July 20, 2005S.Abdullin SUSY Triggers9 More Triggers For SUSY Lepton + MET - SM bkgd. : normalize predictions for W and tt - might add smth. to SUSY signal, especially if  decay leptonically - MET+lepton+jet might be too complicated, so - lepton + MET (above) - jet + MET (exists) - lepton + jet (1/2 exists, for electrons) 2 leptons + 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

July 20, 2005S.Abdullin SUSY Triggers10 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.

July 20, 2005S.Abdullin SUSY Triggers11 QCD Multijet Rate Issue 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 All previous rate calculations have been made with PYTHIA (shower model) Now a preliminary comparison of the inclusive jet E T 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

July 20, 2005S.Abdullin SUSY Triggers12 Inclusive Jet ET Distributions For low-Et and “medium”-Et 3d and 4th jets the difference does not look significant Harder jet E T cuts to be investigated !

July 20, 2005S.Abdullin SUSY Triggers13 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 4 th jets inclusive distributions show a good Agreement between ALPGEN and PYTHIA

July 20, 2005S.Abdullin SUSY Triggers14 Backup Slides

July 20, 2005S.Abdullin SUSY Triggers15 DAQ TDR mSUGRA Test Points Tevatron mass reach

July 20, 2005S.Abdullin SUSY Triggers16 R-Parity Violation Scenario

July 20, 2005S.Abdullin SUSY Triggers17 Probing Points with R-Parity

July 20, 2005S.Abdullin SUSY Triggers18 L2 MET Distributions Similar to t t _

July 20, 2005S.Abdullin SUSY Triggers19 Number of L2 Jets

July 20, 2005S.Abdullin SUSY Triggers20 Leading L2 Jets

July 20, 2005S.Abdullin SUSY Triggers21 Hybrid Genetic Algorithm (I)

July 20, 2005S.Abdullin SUSY Triggers22 Hybrid Genetic Algorithm (II)

July 20, 2005S.Abdullin SUSY Triggers23 Hybrid Genetic Algorithm (III)

July 20, 2005S.Abdullin SUSY Triggers24 QCD Simulation with PYTHIA P T > 20 and 120 GeV Official CMS Production data cards ^ To put ALPGEN and PYTHIA data on the common ground a cut of 120 GeV is applied on the 1st jet E T in both samples

July 20, 2005S.Abdullin SUSY Triggers25 ALPGEN samples ALPGEN v201 Q 2 =  P T 2 (parton) PDFs CTEQ5L Matching scheme CKKW (M Mangano impementation in Alpgen, see Jet parameters for matching: E T (jet) > 15 GeV R(jet) = 0.525,  R(parton-jet) <

July 20, 2005S.Abdullin SUSY Triggers26 ALPGEN samples 2-to-2 : N partons =2; P T (parton)>20 (100) GeV; |eta|<5  R(parton-parton) >0.7 2-to-3 : N partons =3; P T (parton)>20 (100) GeV; |eta|<5  R(parton-parton) >0.7 2-to-4 : N partons =4; P T (parton)>20 (100) GeV; |eta|<5  R(parton-parton) >0.7 (parton= outgoing parton)

July 20, 2005S.Abdullin SUSY Triggers27 samples cross sections sample  (matched-alp)  (unw-alp) matching   (pythia) mb 0.8 mb mb 0.06 mb mb mb total 0.45 mb mb mb sample  (matched-alp)  (unw-alp) matching   (pythia) × mb mb × mb 4 × mb × mb 3.6 × mb total 6.16 × mb × mb × mb 20 GeV 100 GeV

July 20, 2005S.Abdullin SUSY Triggers28 Pseudorapidity distributions 3d jet E T > 100 GeV, 4 th jet E T > 100 GeV