Study of Substructure of High Transverse Momentum Jets Produced in Proton-Antiproton Collisions at sqrt(s)=1.96 TeV

Abstract

A study of the substructure of jets with transverse momentum greater than 400 GeV/c produced in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron Collider and recorded by the CDF II detector is presented. The distributions of the jet mass, angularity, and planar flow are measured for the first time in a sample with an integrated luminosity of 5.95 fb^-1. The observed substructure for high mass jets is consistent with predictions from perturbative quantum chromodynamics.

Figures (3)

• Figure 1: The normalized jet mass distribution for Midpoint jets with $p_{T} > 400$$\rm GeV\!/{\it c}$ and $|\eta|\in (0.1,0.7)$. The uncertainties shown are statistical (black lines) and systematic (yellow bars). The theory predictions for the jet function for quarks and gluons are shown as solid curves and have an estimated uncertainty of $\sim30$%. We also show the pythia MC prediction (red dashed line). The inset compares Midpoint (full black circles) and anti-k$_t$ (open green squares) jets.
• Figure 2: The angularity distribution for Midpoint jets with $p_{T} > 400$$\rm GeV\!/{\it c}$ and $|\eta|\in (0.1,0.7)$. We have applied cuts to reject $t\, \overline{t}$ events and required that $m^{jet1} \in(90,120)$$\rm GeV\!/{\it c}^2$. We also show the pythia calculation (red dashed line) and the pQCD kinematic endpoints. The inset compares the distributions for Midpoint (full black circles) and anti-k$_t$ (open green squares) jets.
• Figure 3: The planar flow distributions for Midpoint jets with $p_{T} > 400$$\rm GeV\!/{\it c}$ and $|\eta|\in (0.1,0.7)$ after applying the top rejection cuts and requiring $m^{jet1} \in(130,210)$$\rm GeV\!/{\it c}^2$. We also show the pythia QCD (red dashed line) and $t\, \overline{t}$ (blue dotted line) jets, as well as the results from the two jet algorithms (inset). All distributions have been separately normalized to unity. We expect only $\sim10$% of the jets to arise from SM $t\, \overline{t}$ production.