alpgen mc samples jet flavour identifier lepton id plots
Post on 22-Dec-2015
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Alpgen Settings for CMS
Alpgen v2.05 CMS Default kinematic cuts in Alpgen
Pt(l,c,b) > 20 GeV |eta (j,c,b)| < 5.0 |eta(e,mu,tau)| < 3.0 dR(jj)>=0.7 dR(lj)>=0.0 M_top = 175 GeV
Jet Multiplicity
Hard process has to be showered. Afterwards two possible modes:
Inclusive: Events with extra Jets due to the parton shower are kept.
Exclusive: Events with extra jets are rejected. For a exclusive sample set the one with the
highest jet mulitplicity must be a inclusive sample
Cuts in Event Selection
Electron |eta| < 2.4 Pt > 26 GeV
Muon |eta| < 2.1 Pt > 19 GeV
TQAF ID LeptonID >= 1 Track Isolation < 0.1 Likelihood Ratio > 0.5
Jets |eta| < 5 Pt > 30 GeV btag > 0.54 MET > 30
Selection Efficiency W+Jets
W+0 Jets W+1Jet W+2 Jets W+3 Jets W+4 Jets W+5 Jets W+6 Jets
Cross section [pb] 30 000 8 000 2 500 722 174 45 31
Total Events 195 933 191 966 180 937 50 199 72 585 55 209 19 619
2 Jet Bin 3 814 36 005 82 848 22 885 11 520 3 146 155
After Cuts:
All 6 36 808 252 150 53 3
Barrel Electrons 1 3 208 59 38 15 0
Endcap Electrons 1 2 64 28 16 11 1
Muons 4 31 536 165 96 27 2
Efficiency [%] 0.0031 0.019 0.45 0.50 0.21 0.096 0.015
JetslJetsWqq '
JFI – Algorithmic Definition
Find Parton that most likely determines the properties of the jet and assign its flavour as the “true” jet flavour
If b or c quark matches to jet cone (ΔR < 0.3) label jet as b or c jet
Else assign flavour of hardest parton to the jet
JFI – Physics Definition
Match reco jet to initial partons from primary process with ΔR < 0.3
No matching if hard final state radiation changes the parton direction significantly
No flavour assignement if matching is ambigous: >1 initial partons match the jet
Gluon jets splitting to c or b quarks are labeled as gluon
Jet Flavour in W+Jets
0 1 2 3 4 5 6
uds 56.1 57.4 49.4 44.0 40.3 37.6 33.5
c 0.8 12.9 10.9 9.8 8.5 7.7 6.8
b 0 0.2 0.6 0.9 1.1 1.5 2.1
g 43.1 29.4 39.1 45.2 50.1 53.3 57.6
W+Jets Pretag Sample TQAF uses Algorithmic Definition all jets in the events after preselection
Selection Efficiency Wbb+Jets
Wbb+2 Jets Wbb+3 Jets
Cross section [pb] 100
Total Events 147 894 22 982
2 Jet Bin 14 322 788
After Cuts:
All 768 40
Barrel Electrons 199 14
Endcap Electrons 90 3
Muons 479 23
Efficiency [%] 0.52 0.17
JetsbblJetsbbWqq '
Wbb+0/1 Jets not available yet
Selection Efficiency Z+Jets
Z+0 Jets Z+1Jet Z+2 Jets Z+3 Jets Z+4 Jets Z+5 Jets Z+6 Jets
Cross section [pb] 2 436 670 230 66 17 4 3
Total Events 43 814 47 869 46 560 47 913 21 402 4 779 4 185
2 Jet Bin 5 267 12 390 19 310 13 018 2 657 209 26
After Cuts:
All 1 31 86 81 25 5 1
Barrel Electrons 1 12 20 19 4 1 0
Endcap Electrons 0 5 6 10 2 0 0
Muons 0 14 60 52 19 4 1
Efficiency [%] 0.0023 0.065 0.18 0.17 0.12 0.10 0.024
JetsllJetsZqq 0
Selection Efficiency Di-Boson
WW (?) WZ ZZ
Cross section [pb] 10.5 4.3 2.6
Total Events 230 959 200 000 69 478
2 Jet Bin 72 601 59 631 20 239
After Cuts:
All 461 530 65
Barrel Electrons 126 148 14
Endcap Electrons 42 51 5
Muons 293 331 46
Efficiency [%] 0.20 0.27 0.094
llxZW llxZZ llWW
Selection Efficiency
tt Single top
Cross section [pb] 833 250
Total Events 2 732 326 192 400
2 Jet Bin 189 519 85 845
After Cuts:
All 42 463 12 845
Barrel Electrons 13 277 4 074
Endcap Electrons 2 707 795
Muons 26 479 7 976
Efficiency [%] 1.55 6.68
Track Probability Jet Tags Distribution
Peaks stem from bug in CMSW 1.3.6 algorithm. Fixed in CMSSW >= 1.5X