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APS abstracts are due to the conveners by Friday, Jan. 5!!
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About 75 pb-1 Run 1B data was used for the stop to EMu search. Up to now, there are only 4 MC samples(stop55w45, stop70w60, stop90w70 and stop110w80) in the stop-chargino mass space going through showerlibray and reco. The events selection criteria is as following:
Kinematic cuts:
e: Et >= 10 Gev
2.5 >= eta >= -2.5
mu: Pt >= 10 Gev
QUADM < 5
>=1 Jet: Et >= 15 Gev
0.95 >= emf >= 0.05
miss Et: met(3) >= 10Gev, Met(4) >= 10Gev,
Et(e)+Pt(mu)+Met(4) < 100 Gev
2.97 > dphi(emu) > 0.17
2.94 >= Dphi(met,j) > 0.2
E Mu id cuts:
E: emf >= 0.95, iso <0.15
dE/dx < 1.5 or dE/dx > 3.0
Mu: Calmipinn >= 1, IFW4 =< 1
dr(mu,jet) >= 0.5
After the cuts were applied to the 1B data, there are 3 events passed.
stop55w45 stop70w60 stop90w70 stop110w80 BKG 1Bdata
No. of Evts 6.34+-.70 2.88+-.26 1.54+-.10 0.64+-.04 3.32+-.25 3
Note: the No. of Evts of the MC signal and BKG are expected number of events in 75 pb-1(after the kinematic and id cuts). The errors are only statistical. The eff.'s of the MC signal are 0.0166+-0.0018, 0.0252+-0.0022, 0.0454+-0.0031 and 0.0594+-0.0034 respactively.
If I made the assumption that the systematic error of the BKG is +-1.00 events and the systematic error of the luminosity is about 5%, then I could only set the stop mass limit at about 57Gev( I used Marc Paterno's program which is based on the Bayesian statistics to calculate the cross section limit). So I cannot set any limit in the stop-chargino two dimentional mass space(the stop mass must be larger than 60Gev).
My kinematic cuts are already very soft(I did change my kinematic cuts like softening the jet Et cuts or no jet required. But the eff.'s of the MC signal were not improved much). Maybe it is very difficult to set any limit in the stop-chargino two dimentional mass space eventually.
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Naba's talk is available as a postscript file.
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