Particle Production at Large Transverse Momentum with ALICE

TL;DR

This paper reports on the measurement of high transverse momentum particle production in proton-proton and lead-lead collisions at the LHC, revealing significant suppression in heavy-ion collisions indicative of parton energy loss in quark-gluon plasma.

Contribution

It provides detailed transverse momentum distributions and nuclear modification factors for various particles, extending previous measurements to higher momenta and comparing with models and lower-energy results.

Findings

Strong suppression of high-$p_T$ particles in Pb--Pb collisions.

Consistency with large parton energy loss in quark-gluon plasma.

Comparison with RHIC results and energy loss models.

Abstract

We present transverse momentum distributions of inclusive charged particles and identified hadrons in $pp$ and Pb--Pb collisions at $\rs= 2.76$ TeV, measured by ALICE at the LHC. The Pb--Pb data are presented in intervals of collision centrality and cover transverse momenta up to 50 GeV/$c$. Nuclear medium effects are studied in terms of the nuclear modification factor \raa. The results indicate a strong suppression of high-$p_T$ particles in Pb--Pb collisions, consistent with a large energy loss of hard-scattered partons in the hot, dense and long-lived medium created at the LHC. We compare the preliminary results for inclusive charged particles to previous results from RHIC and calculations from energy loss models. Furthermore, we compare the nuclear modification factors of inclusive charged particles to those of identified $\pi^0$, $\pi^{\pm}$, K$^0_s$, and $\Lambda$.