Measurement of neutral mesons in pp and Pb-Pb collisions at mid-rapidity with ALICE

TL;DR

This paper reports on measurements of neutral mesons in proton-proton and lead-lead collisions at the LHC, providing insights into the quark-gluon plasma through suppression patterns at high transverse momentum.

Contribution

It presents new measurements of neutral meson spectra in various collision systems using ALICE detectors, enhancing understanding of jet quenching and energy loss in QGP.

Findings

Observation of meson suppression at high pT in Pb-Pb collisions

Comparison of meson spectra between pp and Pb-Pb collisions

Methodology combining calorimeter and tracking system detection

Abstract

One of the key signatures of the Quark-Gluon Plasma (QGP), is the modification of hadron transverse momentum differential cross-sections in heavy-ion collisions (HIC) as compared to proton-proton (pp) collisions. Suppression of hadron production at high transverse momenta (\pt)~in HIC has been explained by the energy loss of the partons produced in the hard scattering processes which traverse the deconfined quantum chromodynamic (QCD) matter. The dependence of the observed suppression on the \pt~ of the measured hadron towards higher \pt~ is an important input for the theoretical understanding of jet quenching effects in the QGP and the nature of the energy loss. The ALICE experiment at the Large Hadron Collider (LHC) performs measurements of neutral meson inclusive spectra at mid-rapidity in a wide \pt~ range in $pp$, $p$-Pb and Pb-Pb collisions. Neutral mesons ($\pi^{0}$, $\eta$, $\omega$) are reconstructed via complementary methods, using the ALICE electromagnetic calorimeters, PHOS and EMCal, and by the central tracking system, identifying photons converted into $e^+e^-$ pairs in the material of the inner barrel detectors (TPC and ITS). In this presentation, an overview of current $\pi^{0}$ and $\eta$ measurements by the ALICE experiment in HIC and pp collisions will be given.