Measurement of the Inclusive Jet Cross Section using the k_T algorithm in pp-bar Collisions at sqrt(s) = 1.96 TeV with the CDF II Detector

TL;DR

This study measures the inclusive jet production cross section in pbar-p collisions at sqrt(s)=1.96 TeV using the k_T jet algorithm with 1.0 fb^-1 of CDF Run II data, extending the pT reach to about 700 GeV/c across |y|<2.1. The analysis meticulously corrects for detector effects, pile-up, and hadronization using detailed MC simulations and unfolding to the hadron level, and compares the results to NLO pQCD predictions with hadron-level corrections. The data show good agreement with NLO predictions over the full pT and rapidity range, providing important constraints on the gluon PDF and validating the k_T approach in a hadron collider environment. These measurements enhance the precision of PDF fits and demonstrate the robustness of jet reconstruction and unfolding methods in high-energy hadron collisions.

Abstract

We report on measurements of the inclusive jet production cross section as a function of the jet transverse momentum in pp-bar collisions at sqrt{s} = 1.96 TeV}, using the k_T algorithm and a data sample corresponding to 1.0 fb^-1 collected with the Collider Detector at Fermilab in Run II. The measurements are carried out in five different jet rapidity regions with |yjet| < 2.1 and transverse momentum in the range 54 < \ptjet < 700 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.

Figures (11)

• Figure 1: Elevation view of one half of the CDF detector displaying the components of the CDF calorimeter.
• Figure 2: Measured trigger efficiencies as a function of $p_{\rm T, \rm cal}^{\rm jet}$ for different trigger paths and in the region $0.1 < | y^{\rm jet}_{\rm cal}| < 0.7$.
• Figure 3: Ratio $\sigma_{p_{\rm T}^{\rm jet}}^{\rm data}/\sigma_{p_{\rm T}^{\rm jet}}^{\rm mc}$ as a function of the average $p_{\rm T, \rm cal}^{\rm jet}$ of the dijet event, in different $| y^{\rm jet}_{\rm cal}|$ regions, before (black squares) and after (open circles) corrections have been applied (see Section VII). The solid lines are fits to the corrected ratios. The dashed lines indicate a $\pm 8 \%$ relative variation considered in the study of systematic uncertainties.
• Figure 4: Ratio $\beta_{\rm data}/\beta_{\rm mc}$ as a function of $p_{\rm T, \rm cal}^{\rm jet}$ in different $| y^{\rm jet}_{\rm cal}|$ regions. The solid lines show the nominal parameterizations based on fits to the ratios. In the region $| y^{\rm jet}_{\rm cal}| > 1.1$, the dashed lines indicate different parameterizations used to describe the ratios at high $p_{\rm T, \rm cal}^{\rm jet}$, and are considered in the study of systematic uncertainties.
• Figure 5: Correlation $\langle p_{\rm T,\rm had}^{\rm jet} - p_{\rm T, \rm cal}^{\rm jet} \rangle$ versus $\langle p_{\rm T, \rm cal}^{\rm jet}\rangle$, as extracted from pythia tune a simulated event samples, in the different $| y^{\rm jet}_{\rm cal}|$ regions.