1. Update on H  4l analysis A. Khodinov * and K. Assamagan ** * State University of New York at Stony Brook ** Brookhaven National Laboratory

2. Data set (signal only) Z (*)  e + e - Z (*)   +  - h  ZZ (*) m h = 130 GeV h  4e   h  4   h  2e2  

3. Framework details Number of Events 100.000 GeneratorPythia 6.217 (6.5.0) no filters Fully simulated with ATLSIM (6.5.0) VDC dataset simul_000033 geometry leveldc1 (  ) Reconstructed withATHENA (7.0.2 and 7.5.0) Job Options fileRecExCommon_jobOptions.txt Additional MC TruthSpcl_MC (F.Paige and I.Hinchliffe)

4. Kinematical cuts as in TDR 1.e 1 + e 2 - or   +   - with p T >20 GeV (leading pair) e 3 + e 4 - or   +   - with p T >7 GeV (following pair) 2. Calculate invariant Z mass  GeV or (  6 GeV) m 12 = m Z  15 GeV or (  6 GeV) GeV m 34 > 20 GeV

5. Additional requirements (Our own) TRD + combinatorial treatment Instead of taking just the 2 hardest leptons as the leading pair, we look though all the possible 4 lepton combinations for the leading and following pairs but retain the combination where the leading pair is best reconstructed (we do not require hardest p T s): e 1 + e 2 - or   +   - with p T >20 GeV min(M z - M ld )

6. Z-mass constraint Assuming the leading lepton pair come from an on-shell Z of mass m Z, rescale 4-momentums of the 2 leading leptons so that: p  pm 0 /m ll Where m ll is the measured (reconstructed) invariant mass of the 2 leading leptons Do this before reconstructing the H mass To find m 0, on event by event basis we convolute detector resolution with the Breit-Wigner shape for Z: m 0 = max ( Gaussian(m ll,  0 ) * BW(m Z,  Z ) ) where  0 is the detector resolution (by fitting m ll without the mass constraint )

7. Leading M ll cut = Mz+-6 GeV Mass constraint applied  2.7 Norm ECAL factor =1/0.9845 mean 129.9  mean 129.9  mean 129.9  mean 130.2  h4h4 h  4e h  2e2  7.0.2 + FORTRAN (PAW)

8. single muon reconstruction Fortran 7.0.2 AOD 7.5.0

9. AOD 7.5.0 No mass constraint! Muid Combined Leading M ll cut = Mz+-6 GeV h4h4

10. Summary and plans Work on the example of analysis h   l using AOD. Our old-fashioned fortran analysis is used as the pattern. we are awaiting for STACO (MuonBox+XKalman) to implement into the h   analysis. h  4e and h  2e2  will be added to AOD Analysis