Measurement of isolated photon-hadron and jet correlations in 5 TeV pp and p-Pb collisions with the ALICE detector at the LHC

TL;DR

This paper reports on measurements of photon-hadron and jet correlations in 5 TeV pp and p-Pb collisions, exploring a new low transverse momentum range with innovative background suppression techniques.

Contribution

It introduces a novel method combining high rate and low-momentum tracking to access previously unexplored kinematic ranges in photon-jet correlation measurements.

Findings

Successful measurement of photon-hadron and jet correlations in the 12-30 GeV/c range.

Implementation of advanced background reduction techniques.

First results in this low pT range with ALICE detector.

Abstract

Photon-jet correlations are a promising channel for the study of parton energy loss in nuclear collisions. While existing measurements in pp and nuclear collisions have used high energy photons and jets, we focus on an unexplored kinematic range given by $12<p_{\mathrm{T}}<30$ GeV/$c$ photons and the corresponding low jet $p_{\mathrm{T}}$. We present results obtained using 5.02 TeV pp and p-Pb collisions. A combination of isolation and electromagnetic shower-shape variables is used to reduce the large background from meson decays and fragmentation photons. We show how the access to this kinematic range of hard probes was achieved with a novel combination of high rate and low-momentum tracking using the electromagnetic calorimeters and the inner tracking system of the ALICE experiment.