Suppression of neutral pion production at large transverse momentum measured with the ALICE experiment in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV

TL;DR

This paper reports measurements of neutral pion production at high transverse momentum in Pb-Pb collisions at 2.76 TeV, showing suppression effects compared to proton-proton collisions, using data from the ALICE experiment.

Contribution

First measurement of neutral pion spectra at high transverse momentum in Pb-Pb collisions at LHC energies using multiple detection methods.

Findings

Significant suppression of neutral pion yields in Pb-Pb compared to pp collisions.

Consistent results across different detector subsystems and analysis techniques.

Quantitative nuclear modification factor $R_{AA}$ indicating medium effects.

Abstract

The ALICE collaboration at the LHC has measured the transverse momentum spectra of neutral pions via their two photon decay in pp and Pb$-$Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV over a broad transverse momentum range with different subsystems: with the electromagnetic calorimeters PHOS and EMCAL and with photon conversions in the inner material of the detectors using $e^{+}e^{-}$ pairs reconstructed with the Central Tracking System. In this report, neutral pions production is compared between pp and Pb$-$Pb collisions measured with conversion photons in terms of the nuclear modification factor, $R_{AA}$, for different centrality selections of the Pb$-$Pb data sample.