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Search for Quark Substructure in the angular distribution of dijets produced in ppbar collisions at sqrt(s)=1.96 TeV.
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Primary contacts:
L. Pondrom, Y. Shon
University of Wisconsin
for the CDF Collaboration
Public Note
Abstract
CDF dijet data have been analyzed to search for evidence for quark substructure
in the angular distributions. The data consist of 11,903,325 events obtained with the single
jet E_T>100 GeV trigger, and an integrated luminosity of
1109 pb-1. No evidence for quark substructure was found, and a
limit on the coupling parameter Lambda>2.4 TeV 95% confidence
was obtained. Systematic uncertainties dominate the limit.
Results
Plots and Figures
Angular distributions in the 600 GeV mass bin
Data&lowast 0.6 compared to Pythia Monte Carlo for two choices of hard scale
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Angular distributions in the 700 GeV mass bin
Data&lowast 0.6 compared to Pythia Monte Carlo for two choices of hard scale
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Angular distributions in the 800 GeV mass bin
Data&lowast 0.6 compared to Pythia Monte Carlo for two choices of hard scale
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Angular distributions in the 900 GeV mass bin
Data&lowast 0.6 compared to Pythia Monte Carlo for two choices of hard scale
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Best fit Angular Distribution in the 600 GeV mass bin
pT2 is favored in the fit
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Best fit Angular Distribution in the 700 GeV mass bin
pT2 is favored in the fit
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Best fit Angular Distribution in the 800 GeV mass bin
pT2 is favored in the fit
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Best fit Angular Distribution in the 900 GeV mass bin
Limited statistics in the highest mass bin
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Quark substructure parameter Λ in Pythia Monte Carlo
Sensitivity of the angular distribution to Λ 600 GeV mass bin
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Quark substructure parameter Λ in Pythia Monte Carlo
Sensitivity of the angular distribution to Λ 700 GeV mass bin
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Quark substructure parameter Λ in Pythia Monte Carlo
Sensitivity of the angular distribution to Λ 800 GeV mass bin
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Quark substructure parameter Λ in Pythia Monte Carlo
Sensitivity of the angular distribution to Λ 900 GeV mass bin
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Ratios R(Λ)/R(∞) for various values of Λ versus (mass)4
R(Λ)=(1<χ<10)/(15<χ<25)
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Quadratic fit to the slopes of the previous plot versus (1/Λ)4
This is the Monte Carlo relation between the slope and Λ
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Ratios R(data)/R(∞) versus (mass)4
Systematic uncertainties are included in the error bars. The slope = -0.16 ± 0.08
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Confidence level contours from a set of pseudoexperiments
Various upper limits on the slope are shown on the plot
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