Update on Dijet Angular Distributions

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Update on Dijet Angular Distributions

• Leonard Apanasevich
• University of Illinois at Chicago
• apana_at_fnal.gov

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Dijet Angular Distributions
Analysis Strategy
JetET150

• Use data-driven approach
• Only use events where single jet trigger is
  fully efficient
• Same prescale factors as in inclusive jet
  analysis
• Each dijet mass bin only uses data from a single
  primary dataset
• Shape analysis
• Observable 1/s ds/d?

JetET110
JetET80
JetET50
JetET30
JetET20
M22pT2(cosh(ln(?))1)
assuming pT1pT2
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Dijet Angular Variables

• Angular distributions
• plotted as a function
• of the variable ? exp(2y)
• where yy1 y2/2
• Two cuts investigated
• ylt1.5 and yboost lt 1.5
• ? lt 20 and y1,y2 lt 3
• ylt1.5 and yboost lt 0.5
• ? lt 20 and y1,y2 lt 2
• where yboost y1 y2/2

Using ylt1.5 and yboost lt 1.5 for This
presentation
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Comparison with GenJets
No resolution unsmearing performed
Reco/Gen
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Uncertainty due to Energy Scale
Rough first guess for energy scale uncertainty
with 10 pb-1 data

• Barrel
• 10 for pT lt 100 GeV
• then linearly increasing to 20 _at_ 2TeV
• Endcaps
• Barrel uncertainty plus additional 10 to 100 GeV
• Extrapolate to 20 _at_ 1 TeV
• Forward
• Barrel uncertainty plus additional 15 _at_ 100 GeV
• Extrapolate to 30 _at_ 500 GeV

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Comparison with Theory
L 10pb-1

• No resolution unsmearing performed
• Stat and sys uncertainty added in quadrature
• LO calculation
• scale µR µF pT
• Pdf CTEQ6L
• Two choices of compositeness scale shown
• ? 3.0 TeV
• ? 5.0 TeV