Overview of ALICE results on azimuthal correlations using neutral- and heavy-meson triggers

TL;DR

This paper reviews ALICE's measurements of azimuthal correlations involving neutral and heavy-flavor mesons in proton-proton and lead-lead collisions, providing insights into medium modifications of high-momentum particle interactions.

Contribution

It provides an overview of azimuthal correlation measurements with neutral and heavy-flavor mesons, comparing experimental results with theoretical models in different collision systems.

Findings

Strong suppression of high-$p_T$ hadrons and mesons in Pb-Pb collisions.

Azimuthal correlations reveal medium-induced modifications.

Comparison with models tests predictions about the quark-gluon plasma.

Abstract

The ALICE detector is dedicated to studying the properties of hot and dense matter created in heavy-ion collisions. Among the probes used to investigate these properties are high-momentum particles, which originate in hard-scatterings occurring before the fireball creation. The fragments of hard scatterings interact with the hot and dense matter and via this interaction their spectra and azimuthal distributions are modified. This is probed by the measurement of the nuclear modification factor, where the $p_{\mathrm{T}}$ spectra obtained in Pb-Pb collisions are compared to a pp baseline. A strong suppression of charged hadrons as well as neutral- and heavy-flavor mesons was observed at $p_{\mathrm{T}} > 4$ GeV/$c$. Azimuthal correlations, using high-momentum ($p_{\mathrm{T}} > 4$ GeV/$c$) hadrons as triggers, can provide further insight into how the presence of the medium modifies the final kinematic distributions of the particles. Comparison with theoretical models can be used to test their predictions about the properties of the medium. We give an overview of ALICE azimuthal-correlation measurements of neutral- and heavy-flavor mesons with charged hadrons in pp collisions at $\sqrt{s}=7$ TeV and Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}=2.76$ TeV. We also present a measurement of the $\pi^{0}$ correlation with jets in pp collisions at $\sqrt{s}=7$ TeV.