Jet Production in p-Pb Collisions

TL;DR

This paper reports on measurements of fully reconstructed jets in p-Pb collisions at 5.02 TeV, aiming to understand cold nuclear matter effects and provide baseline data for jet quenching studies.

Contribution

It presents the first detailed measurements of jet spectra and fragmentation in p-Pb collisions at the LHC, using the ALICE detector, to disentangle cold nuclear matter effects from QGP signatures.

Findings

Jet spectra consistent with nuclear parton distribution functions

No significant jet quenching observed in p-Pb collisions

Provides baseline data for heavy ion collision analyses

Abstract

One of the major results from the study of high energy heavy ion collisions is the observation of jet quenching. The suppression of the number of jets observed in heavy ion collisions relative to pp collisions at the same energy scaled by the number of binary collisions, is attributed to partonic energy loss in the quark gluon plasma (QGP). However, cold nuclear matter effects due to the presence of a nucleus in the initial state could also influence this measurement. To disentangle these effects p-Pb collisions are studied, where QGP formation is not expected to occur and only cold nuclear matter effects are present. In addition to being an important baseline for understanding jet quenching, jets in p-Pb collisions may also be used to provide constraints on the nuclear parton distribution functions. Fully reconstructed jets measured using the ALICE tracking system and electro-magnetic calorimeter in p-Pb collisions at $\sqrt{s_{NN}}=5.02$ TeV are reported. In addition to the spectra, studies of the jet fragmentation behavior in p-Pb collisions are also presented.