Medium-induced transverse momentum broadening via forward dijet correlations

Jiangyong Jia,Bo-Wen Xiao,Shu-Yi Wei,Feng Yuan

doi:10.1103/physrevd.101.094008

Abstract

Dijet azimuthal angle correlation is arguably one of the most direct probes of the medium-induced broadening effects. The evidence for such broadening, however, is not yet clearly observed within the precision of current mid-rapidity measurements at RHIC and the LHC. We show that the dijet correlation in forward rapidity from the future LHC RUN3, aided by forward detector upgrades, can reveal this broadening thanks to the steeper jet spectra, suppressed vacuum radiations and lower underlying event background, with a sensitivity comparable to that of the future high-luminosity Au+Au run at RHIC. Dijet correlation measurements at the two facilities together can provide powerful constraints on the temperature dependence of medium transport properties.

Highlights

There has been a lot of evidence that the quark gluon plasma (QGP) has been created in the heavy-ion collisions at RHIC and the LHC
By choosing jets with small radius (e.g., R 1⁄4 0.2) and with the underlying event background (UE) level expected in central collisions at RHIC [34], these systematic uncertainties were shown to be reduced to a reasonable level for dijets down to 30 GeV
We observe that the Δφ distributions in the midrapidity are flatter than those in the forward rapidity at the same pT. This is mainly due to two reasons: (1) the Sudakov factor for the gg channel that dominates in the midrapidity, is much larger than that for the qg channel that dominates in the forward rapidity, (2) it is a common practice to set the factorization scale μf 1⁄4 μb in the Sudakov resummation framework to simplify the formula, which, we find numerically, makes parton shower stronger in the middle rapidity than in the forward rapidity for gg → gg channel at low pT

Summary

INTRODUCTION

There has been a lot of evidence that the quark gluon plasma (QGP) has been created in the heavy-ion collisions at RHIC and the LHC. This RHICLHC complementarity was demonstrated for several full jet observables with the sPHENIX detector in the future RHIC run [34] Another lever arm for extracting the temperature dependence of QGP properties and structures is provided by comparing jet measurements at midrapidity at RHIC with those at forward-rapidity at LHC. This is because the medium produced at forward-rapidity may have a temperature pcloffiffiffisffieffiffirffi to the medium produced at midrapidity at lower sNN, but with a very different space-time dynamics. We show that the forward-rapidity LHC provides a broader kinematic range for detecting the medium-induced broadening effects

DIJET CORRELATION IN FORWARD RAPIDITY IN pp AND AA COLLISIONS

RESULTS

SUMMARY