1. trigger efficiencies for GMSB Andrea Bangert Santa Cruz Institute for Particle Physics April 19 th, 2010 1

2. sample and selection cuts sample: GMSB1, sample 105410 10 TeV collisions (mc08) reconstructed in 15.3.1.6 ATLAS-GEO-02-01-00 software: svnweb.cern.ch/trac/atlasusr/browser/abangert/diphotonGMSB run in athena 15.6.0 selection cuts: MET > 60 GeV H T > 550 GeV, two reconstructed photons p T > 20 GeV eta < 2.5 isEM is tight E T (ΔR < 0.2) / E T < 0.1 2

3. cut flow number of events remaining after each selection cut no trigger EF_g20_loose requires one photon pT > 20 GeV EF_2g20_loose requires two photons pT > 20 GeV initial efficiency of g20_loose is 97.8% Efficiency after all cuts is 100% initial efficiency of 2g20_loose is 78.5% efficiency after all cuts is 99.6% 3

4. p T of gravitino vs MET 4 every GMSB1 event produces two neutralini each neutralino decays to produce gravitino and photon (or Z) left: gravitino with highest p T, right: gravitino with lowest p T gravitino with highest p T determines MET subleading gravitino has less impact on MET

5. p T of gravitino vs p T of photon 5 left: gravitino associated with photon with highest p T right: gravitino associated with subleading photon photon with highest p T is likely to be associated with subleading gravitino gravitino with highest p T is likely to be associated with subleading photon

6. trigger efficiency as function of photon p T 6 left: 2g20_loose (requires 2 photons), right: g20_loose (requires 1 photon) caveat: no matching was done between true photon from neutralino decay and object which fired trigger one can see how the trigger turns on at p T = 20 GeV

7. trigger efficiency vs photon pseudorapidity 7 left: 2g20_loose (requires 2 photons), right: g20_loose (requires 1 photon) cut: p T > 20 GeV caveat: no matching was done one can see how the trigger turns on at η = 2.5

8. trigger efficiency vs MET 8 Large MET indicates high pT for leading gravitino. High p T for leading gravitino indicates lower pT for subleading photon. Is this why efficiency of two photon trigger drops slightly as MET increases?

9. trigger efficiency vs sum of E T 9 sum of ET weak production strong production sum of E T in calorimeter clusters

10. conclusion good news EF_g20_loose and EF_2g20_loose almost 100% efficient for events which pass selection cuts no prescale at L = 10 31 1/cm 2 s 2g20 has no prescale at L = 10 32 1/cm 2 s not so good: g20 has prescale of 10 at L = 10 32 1/cm 2 s twiki.cern.ch/twiki/bin/view/Atlas/TriggerPhysicsMenu caveat model represents single point in GMSB phase space goal run over MC09 sample in athena 15.6.7 problem trigger configuration dysfunctional in 15.6.7 10