Measurement of inclusive jet cross sections in pp and PbPb collisions at sqrt(s[NN]) = 2.76 TeV

TL;DR

This paper measures inclusive jet cross sections in proton-proton and lead-lead collisions at 2.76 TeV using CMS data, revealing how jet production and suppression vary with collision centrality and jet parameters.

Contribution

It provides the first detailed comparison of jet spectra and nuclear modification factors in pp and PbPb collisions at this energy, including the dependence on jet size parameter.

Findings

Jet spectra in pp are over-predicted by NLO QCD calculations for small R.

Jet suppression in PbPb increases with collision centrality.

Nuclear modification factors are independent of jet size parameter within the measured range.

Abstract

Inclusive jet spectra from pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV, collected with the CMS detector at the LHC, are presented. Jets are reconstructed with three different distance parameters (R = 0.2, 0.3, and 0.4) for transverse momentum (pT) greater than 70 GeV and pseudorapidity abs(eta) < 2. Next-to-leading-order quantum chromodynamic calculations with non-perturbative corrections are found to over-predict jet production cross sections in pp for small distance parameters. The jet nuclear modification factors for PbPb compared to pp collisions, show a steady decrease from peripheral to central events, along with a weak dependence on the jet pT. They are found to be independent of the distance parameter in the measured kinematic range.