Azimuthal anisotropy of charged jet production in $\mathbf{\sqrt{{\textit s}_{\rm NN}}}$ = 2.76 TeV Pb--Pb collisions

TL;DR

This paper measures the azimuthal anisotropy of charged jet production in lead-lead collisions at 2.76 TeV, revealing significant elliptic flow effects and comparing results with models and other particle measurements.

Contribution

It provides the first detailed measurement of charged jet azimuthal anisotropy in heavy-ion collisions, correcting for flow and detector effects, and compares with theoretical predictions.

Findings

Significant elliptic flow ($v_2$) observed in semi-central collisions.

Qualitative agreement with jet and particle $v_2$ measurements and models.

Results support hydrodynamic flow influence on jet production.

Abstract

Measurements of charged jet production with respect to the second-order harmonic event plane, quantified as $v_{2}^{\mathrm{ch~jet}}$, in $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV Pb--Pb collisions are presented. The contribution of hydrodynamic flow to the underlying event energy is corrected for on a jet-by-jet basis. Remaining effects from instrumental resolution and regional fluctuations in the energy density of the underlying event are corrected for by unfolding. Significant $v_{2}^{\mathrm{ch~jet}}$ is observed in semi-central collisions. Qualitative agreement is found with $v_{2}^{\mathrm{ch+em jet}}$ of jets reconstructed from charged and neutral fragments and $v_2$ of single charged particles, as well as with predictions from the JEWEL Monte Carlo model.