Ratio Of Transverse Energy Research Articles

Measurement of dN/dη and dET/dη in PbPb collisions with CMS

Abstract The charged particle multiplicity and transverse energy in PbPb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy ( s NN ) has been measured over a broad range of pseudorapidity ( η ) and collision centrality using the CMS detector at the LHC. The transverse energy density per unit pseudorapidity ( d E T / d η ) increases faster with collision energy than the charged particle multiplicity d N / d η . This implies that the mean energy per particle is increasing with collision energy. At all pseudorapidities the multiplicity and transverse energy per participating nucleon increases with the centrality of the collision. The ratio of transverse energy per unit pseudorapidity in peripheral to central collisions varies significantly as the pseudorapidity increases from η = 0 to | η | = 5.0 .

Measurement of the Pseudorapidity and Centrality Dependence of the Transverse Energy Density in Pb-Pb Collisions atsNN=2.76 TeV

The transverse energy (E(T)) in Pb-Pb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy (√(s(NN)) has been measured over a broad range of pseudorapidity (η) and collision centrality by using the CMS detector at the LHC. The transverse energy density per unit pseudorapidity (dE(T)/dη) increases faster with collision energy than the charged particle multiplicity. This implies that the mean energy per particle is increasing with collision energy. At all pseudorapidities, the transverse energy per participating nucleon increases with the centrality of the collision. The ratio of transverse energy per unit pseudorapidity in peripheral to central collisions varies significantly as the pseudorapidity increases from η=0 to |η|=5.0. For the 5% most central collisions, the energy density per unit volume is estimated to be about 14 GeV/fm(3) at a time of 1 fm/c after the collision. This is about 100 times larger than normal nuclear matter density and a factor of 2.6 times higher than the energy density reported at √(s(NN))=200 GeV at the Relativistic Heavy Ion Collider.

Systematic studies of the centrality andsNNdependence of thedET/dηanddNch/dηin heavy ion collisions at midrapidity

The PHENIX experiment at the relativistic heavy ion collider (RHIC) has measured transverse energy and charged particle multiplicity at midrapidity in $\mathrm{Au}+\mathrm{Au}$ collisions at center-of-mass energies $\sqrt{{s}_{\mathrm{NN}}}=19.6,130$, and $200\phantom{\rule{0.3em}{0ex}}\text{GeV}$ as a function of centrality. The presented results are compared to measurements from other RHIC experiments and experiments at lower energies. The $\sqrt{{s}_{\mathrm{NN}}}$ dependence of $dE{}_{T}/d\ensuremath{\eta}$ and $dN{}_{\mathrm{ch}}/d\ensuremath{\eta}$ per pair of participants is consistent with logarithmic scaling for the most central events. The centrality dependence of $dE{}_{T}/d\ensuremath{\eta}$ and $dN{}_{\mathrm{ch}}/d\ensuremath{\eta}$ is similar at all measured incident energies. At RHIC energies, the ratio of transverse energy per charged particle was found to be independent of centrality and growing slowly with $\sqrt{{s}_{\mathrm{NN}}}$. A survey of comparisons between the data and available theoretical models is also presented.