Top @ 10 TeVUpdates on Efficiencies and Event

Shapes

Ken Johns, Venkat Kaushik, Xiaowen Lei

(U. Arizona)

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IntroductionWe updated single lepton selection

reference tables with event numbers after each cut Mc event weight (either 1 or -1) are taken into

account Tables are filled for these samples:

Ttbar: 105200 (mcatnlo), 105206 (acermc) Wenu+Np: 108241, 108242, 108243 Wmunu+Np: 108244, 108245, 108246

Problems: For 105205 sample, we only see dilepton events. Is

this a problem with the generation? We will update the numbers for the background once

the new good samples are ready. On the twiki page

https://twiki.cern.ch/twiki/bin/viewauth/AtlasProtected/TopCSBenchMark#Single_lepton_channel

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Cuts from the Spreadsheet

Cut 1 – lepton trigger EF_e20i or EF_mu20

Cut 2 – exactly 1 lepton with Pt>20GeV

Cut 3 – MET>20GeVCut 4 – 4 good jets with Pt>30GeVCut 5 – 3 good jets with Pt>40GeVCut 6 – 150<m_jj<190GeV

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e+jet Efficiencies

Efficiencies

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mu+jet Efficiency

Efficiencies

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10 TeV Top

We made preliminary comparison of 105200 samples and 105206 samples

To be added: detailed generation infoLooked at jet multiplicity, jet pt, and

lepton pt spectrumResults are compartible

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Comparison of 105200 and 105206

Jet pt:

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Comparison of 105200 and 105206

Jet mulplicity:

Lepton pt spectrum:

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Comparison of 105200 and 105206

m(jjj) where jjj == highest vector Pt (e+jets):

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Topological Variables We use 108243/108247 samples for

background, instead of using all 108241(2,3)/108245(6,7) samples.

Cuts have higher efficiency on 8243 and 8247, thus we get more statistics, and thus the influence of the “repeated events” is relatively small.

Use events which passed cuts 1-5. Added masschisq as one of the event shape

variables. A total number of 12 variables are currently used.

masschisq = (hadTopMass – TopPDGmass)^2/Sigmajjb^2 + (lepTopMass – TopPDGmass)^2/Sigmalnb^2 + (hadWmass – WPDGmass)^2/Sigmajj^2

Improved the fits to the template functions.

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Topological Variables – e+jets

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Topological Variables – e+jets

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Topological Variables – e+jets

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Topological Variable Fits – e+jets

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Topological Variable Fits – e+jets

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Topological Variable Fits – e+jets

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Topological Likelihood Lt

e+jets:

mu+jets:

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Work in Progress to Optimize Topo Vars

We are comparing the jet pt distributions between sig and bkg, for 1st,2nd,3rd,4th leading jets, to find out what serves as the best combination.

We are also learning from CDF. Some of the variables are similar (not exactly the

same, for example, they use 3 leading jets for most variables instead of 4)

They also use some different variables

Also want to try TMVA package to find the best discrimator.

A simple macro for fitting the ratio is ready. In the process of preparing simple mixed sample to

test the likelihood

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Different Topo Variables from CDF

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Conclusions

Updated the single-lepton efficiency table Numbers for the background will be updated

as soon as we get bug-fixed samples

Made preliminary comparison between 105200 and 105206 samples

Improved fits and top likelihood Next will test the likelihood in ratio fitting Will continue to optimize likelihood

We also would like to study lepton isolation for the trigger

Need additional background samples to increase the statistics