Jet tomography of high-energy nucleus-nucleus collisions at next-to-leading order

TL;DR

It is demonstrated that jet observables are highly sensitive to the characteristics of the vacuum and the in-medium QCD parton showers and techniques that exploit this sensitivity to constrain the mechanism of quark and gluon energy loss in strongly interacting plasmas are proposed.

Abstract

We demonstrate that jet observables are highly sensitive to the characteristics of the vacuum and the in-medium QCD parton showers and propose techniques that exploit this sensitivity to constrain the mechanism of quark and gluon energy loss in strongly-interacting plasmas. As a first example, we calculate the inclusive jet cross section in high-energy nucleus-nucleus collisions to ${\cal O}(α_s^3)$. Theoretical predictions for the medium-induced jet broadening and the suppression of the jet production rate due to cold and hot nuclear matter effects in Au+Au and Cu+Cu reactions at RHIC are presented.

Figures (3)

• Figure 1: Comparison of the NLO calculation to STAR experimental data Abelev:2006uq on the inclusive jet cross section for R=0.4 (top panel). The variation of the jet cross section with the cone size $R$ for $E_T=10,\,40$ GeV around midrapidity at RHIC is also shown (bottom panel).
• Figure 2: The differential jet shape in vacuum $\psi^{\rm vac.}(r,R)$ is contrasted to the medium-induced contribution $\psi^{\rm med.}(r,R)$ by a $E_T = 30$ GeV quark in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}=200$ GeV. The insert illustrates a method for studying the characteristics of these parton showers.
• Figure 3: Transverse energy dependent nuclear modification factor $R_{AA}^{\rm jet}$ for different cone radii $R$ in $b=3$ fm Au+Au (top panel) and Cu+Cu (bottom panel) collisions at $\sqrt{s_{NN}}=200$ GeV. Inserts show ratios of jet cross sections for different $R$ in nuclear reactions versus $E_T$.