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Update on H g 4l analysis. A. Khodinov * and K. Assamagan ** * State University of New York at Stony Brook ** Brookhaven National Laboratory. Data set (signal only). h g ZZ (*) m h = 130 GeV. Z (*) g e + e - Z (*) g m + m -. h g 4e 25% c h g 4 m 25% h g 2e2 m 50%.
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Update on Hg4l analysis A. Khodinov* and K. Assamagan** * State University of New York at Stony Brook ** Brookhaven National Laboratory
Data set (signal only) hgZZ(*) mh = 130 GeV Z(*)ge+e- Z(*)gm+m- hg4e 25% chg4m25% hg2e2m 50%
Framework details • Number of Events 100.000 • Generator Pythia 6.217 (6.5.0) no filters • Fully simulated with ATLSIM (6.5.0) • VDC dataset simul_000033 • geometry level dc1 (|h|< 2.7) • Reconstructed with ATHENA (7.0.2 and 7.5.0) • Job Options file RecExCommon_jobOptions.txt • Additional MC Truth Spcl_MC (F.Paige and I.Hinchliffe)
Kinematical cuts as in TDR • e1+e2- or m1+m2- with pT>20 GeV (leading pair) • e3+e4- or m3+m4- with pT>7 GeV (following pair) • 2. Calculate invariant Z mass • m12 = mZ 15GeVor ( 6 GeV) • m34 > 20GeV
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 pTs): • e1+e2- or m1+m2- with pT>20 GeV min(Mz-Mld)
Z-mass constraint • Assuming the leading lepton pair come from an on-shell Z of mass mZ, rescale 4-momentums of the 2 leading leptons so that: p pm0/mll Where mll is the measured (reconstructed) invariant mass of the 2 leading leptons • Do this before reconstructing the H mass • To find m0, on event by event basis we convolute detector resolution with the Breit-Wigner shape for Z: m0 = max ( Gaussian(mll, s0) * BW(mZ,GZ) ) where s0 is the detector resolution (by fitting mll without the mass constraint )
mean 129.9 s 1.834 mean 129.9 s 1.890 mean 130.2 s 1.56 hg4e hg4m 7.0.2 + FORTRAN (PAW) Leading Mll cut = Mz+-6 GeV Mass constraint applied mean 129.9 s 1.895 hg2e2m |h|<2.7 Norm ECAL factor =1/0.9845
hg4m AOD 7.5.0 No mass constraint! Muid Combined Leading Mll cut = Mz+-6 GeV
Summary and plans • Work on the example of analysis hg4l using AOD. Our old-fashioned fortran analysis is used as the pattern. • we are awaiting for STACO (MuonBox+XKalman) to implement into the hg4m analysis. • hg4e and hg2e2m will be added to AOD Analysis