Measurement of jet spectra with charged particles in Pb-Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV with the ALICE detector

TL;DR

This paper measures jet spectra in lead-lead collisions at 2.76 TeV using the ALICE detector, revealing significant jet suppression in central collisions and analyzing the effects of background and fragmentation bias.

Contribution

It provides the first detailed measurement of charged-particle jet spectra in Pb-Pb collisions at this energy, including background correction and fragmentation bias analysis.

Findings

Strong jet suppression observed in central collisions.

Background fluctuations are effectively corrected by unfolding.

Fragmentation bias is consistent across centralities.

Abstract

We report a measurement of transverse momentum spectra of jets detected with the ALICE detector in Pb-Pb collisions at $\sNN=2.76$ TeV. Jets are reconstructed from charged particles using the anti-\kt jet algorithm. The transverse momentum of tracks is measured down to 150 MeV/$c$ which gives access to the low \pt fragments of the jet. The background from soft particle production is determined for each event and subtracted. The remaining influence of underlying event fluctuations is quantified by embedding different probes into heavy-ion data. The reconstructed transverse momentum spectrum is corrected for background fluctuations by unfolding. We observe a strong suppression in central events of inclusive jets reconstructed with radii of 0.2 and 0.3. The fragmentation bias on jets introduced by requiring a high \pt leading particle which rejects jets with a soft fragmentation pattern is equivalent for central and peripheral events.