One Lepton Mode Background MT and new MT method (including systematic errors). SUSY Background meeting (CSC1&2) 27. Nov 2007 Ginga Akimoto , S.Asai, Y.Kataoka, N.Kanaya The University of Tokyo, ICEPP. Table of Contents. Update Digest of BG estimation Systematic Error Study
One Lepton Mode BackgroundMT and new MT method (including systematic errors)
SUSY Background meeting (CSC1&2)
27. Nov 2007
Ginga Akimoto , S.Asai, Y.Kataoka, N.Kanaya
The University of Tokyo, ICEPP
I have already shown the detail of our method in the previous meeting, so I focus on the systematic errors today.
2nd Lepton (PT>10GeV) veto
Def :: Effective Mass : add Lepton PT
Def :: Transverse Sphericity : add Lepton
Systematic Error Study of ( lepton efficiency , Energy Scale, STACO muon id selection , MC @ NLO)
BG estimation with K factor
Used samples are the CSC full-simulation samples (v220.127.116.11) and systematic error samples (including fast simulation) . [same to previous meeting]
In Addition to these , we use ATLFAST alpgen samples to study lepton efficiency.
The background distributions of One Lepton Channel are estimated with Control Sample.
(detail has already shown in the previous many meetings.)
Magenta with error :
estimated BG with C.S.
Black line : (truth) all BG process
(ttï bblnln dominant)
Events number is also well reproduced.
We checked these systematic errors
[BG] means real BG.
[BG est] is estimated BG(MT w/o SUSY and new MT with SUSY).
[BG(syst.)/BG(original)] is [BG] difference from original sample.
These figures show mET and Meff distribution of ATLFAST. We assumed 2% lepton efficiency (Results after 2% Eff are next page).
The level of contamination (# of SUSY ratio : [Control Sample] over [Signal Region] ) is assumed to be 0.7 (by MC average from SU1 to SU3 CSC Full). These factors are deferent with each SUSY models by 0.1. So we changed it to 0.6 and 0.8 and applied new MT method.
0.8 :we overestimate contamination
0.6 : we underestimate contamination