Measurements of the Nuclear Modification Factor for Jets in Pb+Pb Collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV with the ATLAS Detector

TL;DR

This paper reports measurements of jet production in proton-proton and lead-lead collisions at 2.76 TeV, revealing significant jet suppression in central heavy-ion collisions and analyzing how this suppression varies with jet momentum and rapidity.

Contribution

It provides the first detailed measurement of the nuclear modification factor for jets at the LHC energy of 2.76 TeV with the ATLAS detector, highlighting jet suppression patterns.

Findings

Jets are suppressed by about a factor of two in central Pb+Pb collisions.

The nuclear modification factor $R_{AA}$ slightly increases with jet transverse momentum.

No significant variation of $R_{AA}$ with rapidity was observed.

Abstract

Measurements of inclusive jet production are performed in $pp$ and Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV with the ATLAS detector at the LHC, corresponding to integrated luminosities of 4.0 $\mathrm{pb}^{-1}$ and 0.14 $\mathrm{nb}^{-1}$, respectively. The jets are identified with the anti-$k_t$ algorithm with $R=0.4$, and the spectra are measured over the kinematic range of jet transverse momentum $32 < p_{\mathrm{T}} < 500$ GeV, and absolute rapidity $|y| < 2.1$ and as a function of collision centrality. The nuclear modification factor, $R_{\mathrm{AA}}$, is evaluated and jets are found to be suppressed by approximately a factor of two in central collisions compared to $pp$ collisions. The $R_{\mathrm{AA}}$ shows a slight increase with $p_{\mathrm{T}}$ and no significant variation with rapidity.