First CMS results from PbPb collisions

Abstract

We present the first results on PbPb collisions at √ s N N = 2.76 TeV with the CMS experiment at the LHC. This is a huge energy jump of a factor of 14 over RHIC creating the hottest matter ever produced in a laboratory. The prime goal of this research is to study the fundamental theory of the strong interaction (QCD) in extreme conditions of temperature, density and parton momentum fraction. We give an overview of the measurements by CMS in PbPb collisions both in "soft" and "hard" regimes. The first results on the reconstruction of jets, Z and quarkonia are described. These signals are the probes of the hottest and densest phases of the reaction. Also, an overview of the bulk observables such as charged hadron multiplicity, low p T inclusive hadron identified spectra and elliptic flow which provide information on the collective properties of the system is given. AbstractWe present the first results on PbPb collisions at √ s NN = 2.76 TeV with the CMS experiment at the LHC. This is a huge energy jump of a factor of 14 over RHIC creating the hottest matter ever produced in a laboratory. The prime goal of this research is to study the fundamental theory of the strong interaction (QCD) in extreme conditions of temperature, density and parton momentum fraction. We give an overview of the measurements by CMS in PbPb collisions both in "soft" and "hard" regimes. The first results on the reconstruction of jets, Z and quarkonia are described. These signals are the probes of the hottest and densest phases of the reaction. Also, an overview of the bulk observables such as charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow which provide information on the collective properties of the system is given.