Top @ 10 TeVUpdates on Efficiencies and Event

Shapes

Ken Johns, Venkat Kaushik, Xiaowen Lei

(U. Arizona)

Single lepton + jets channel

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EfficienciesWe 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 the following samples:

Ttbar: 105200 (mcatnlo), 105206 (acermc) in e/mu + jets chn Wenu+Np: 108241, 108242, 108243; Wmunu+Np: 108244,

108245, 108246 Problems and to-dos:

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 bug-fixed samples are ready.

Will fill the table for KKgluon or Z’->ttbar samples once we can find rel14 samples on the grid.

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 5200: T1_McAtNlo_Jimmy; No Full Had; 202.86pb*1.07 5206: AcerMCttbarHerwig; No Full Had; 108.64pb*2.01

As a first step we looked at jet multiplicity, jet pt, and lepton pt spectrum

Loose jet: et > 15GeV, abs(eta) < 2.5 Lepton: plots are without cuts

These plots show that the two samples are almost identical. No big difference are spotted

Further comparison will be made

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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 Cut 6 leaves too few events for the background

Added masschisq as one of the event shape variables masschisq = (hadTopMass – TopPDGmass)^2/Sigmajjb^2 +

(lepTopMass – TopPDGmass)^2/Sigmalnb^2 + (hadWmass – WPDGmass)^2/Sigmajj^2

A total number of 12 transformed variables are currently used

See following slides for comparison plots

Improved fits to the template functions See following slides for fittings

Topological Variables – e+jetslog(ht):

sum(et) for jets et>15GeV

log(ht_2):log(et_j1+et_j2)

log(ht_3):log(et_j3+et_j4)

log(ht’_2):log(Sum(et)_j234/

Sum(pz)_j1234)

log(he) is also used but not shown here

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Topological Variables – e+jets

log(centrality):log(ht/he)

exp(-11apla):apla = 3/2Q_1

log(sphe):sphe =

3/2(Q_1+Q_2)

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Topological Variables – e+jetsLog(mjj_min):

minimum dijet mass

Use 4 leading jets

dPhi:angle between

leading lepton and missing et

log(K’_Tmin):minimum dijet

distance * et of the lower in the pair / hadronic W et

masschisq13

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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 to compare different variables and choose the best ones

Some of the variables are similar (not exactly the same, for example, they use 3 leading jets for most variables instead of 4 leading jets)

They also use some different variables

Also want to try TMVA package to find the best likelihood/discrimator

We need to reduce the number of the variables used since a lot of them are similar

A simple macro for fitting the ratio is ready. Will prepare simple mixed sample to test the likelihood

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Different Topo Variables from CDF

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Conclusions Updated semi-leptonic efficiency tables and made

preliminary comparison of 105200 and 105206 samples Have improved fits and top likelihood

Next will test the likelihood in ratio fitting and continue to optimize

We also would like to study lepton isolation for the trigger

Need additional background samples to increase the statistics

Atlfast sample exist but no replicas on the grid? Maybe we should contact W+jets group.

mc08.10768*AlpgenJimmyWenuNp*_pt20.recon.AOD.e349_a68 mc08.10769*AlpgenJimmyWmunuNp*_pt20. recon.AOD.e349_a68

Will do the same for release 14 KKgluon or Z’->ttbar sample once we can find them on the grid

KKgluon not ready yet? Z’->ttbar only privately generated?