Study of high-pT charged particle suppression in PbPb compared to pp collisions at sqrt(sNN)=2.76 TeV

TL;DR

This paper reports measurements of charged particle spectra in PbPb and pp collisions at 2.76 TeV, revealing significant suppression in central PbPb collisions at intermediate transverse momenta, which diminishes at higher momenta.

Contribution

First detailed comparison of charged particle suppression in PbPb versus pp collisions at LHC energies across a wide pt range.

Findings

Suppression factor up to 5 at 5-10 GeV/c in central PbPb collisions.

Suppression decreases to about a factor of 2 at 40-100 GeV/c.

Charged particle yields are significantly modified in heavy-ion collisions.

Abstract

The transverse momentum spectra of charged particles have been measured in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV by the CMS experiment at the LHC. In the transverse momentum range pt = 5-10 GeV/c, the charged particle yield in the most central PbPb collisions is suppressed by up to a factor of 5 compared to the pp yield scaled by the number of incoherent nucleon-nucleon collisions. At higher pt, this suppression is significantly reduced, approaching roughly a factor of 2 for particles with pt in the range pt=40-100 GeV/c.