Geometrical and Dynamical Fluctuations in Pb-Pb, Pb-Nb Interactions
نویسنده
چکیده
The fluctuations in pseudorapidity density are well described by Fritiof and IRIS, model for a bulk of the data at a few high multiplicity events remain unexplained. In these events, the estimated energy density is within the range of values predicated for the onset of the deconfinement phase transition. It is important to know whether fluctuations are, in fact, of statistical nature or geometrical ones or due to some physical process. A fluctuation is not just due to statistical origin if it exceeds five or six standard deviations. Different methods devised to understand the nature of these fluctuations are discussed.
منابع مشابه
Nucleon number dependence of longitudinal radii in ion-ion collisions as a signature of the onset of collective expansion
In an attempt to disentangle the effects of nuclear geometry from those of expansion we study the dependence of the longitudinal radius (RL) on nuclear numbers of colliding ions within a simple model of multiple nucleonnucleon collisions.The model has built in the nuclear geometry but there is no dynamical expansion.In principle, what is significantly beyond models of this type can be considere...
متن کاملEnergy dependence of fluctuations in central Pb+Pb collisions from NA49 at the CERN SPS
The latest NA49 results on fluctuations of multiplicity and average transverse-momentum analyzed on an event-by-event basis are presented for central Pb+Pb interactions over the whole SPS energy range (20A 158A GeV). The scaled variance of the multiplicity distribution decreases with collision energy whereas the ΦpT measure of 〈pT 〉 fluctuations is small and independent of collision energy. Thu...
متن کاملStrangeness production in nuclear interactions at 200AGeV and the number of nucleon- nucleon collisions
Data on mean numbers of Λ, Λ̄, K’s and on the total number < ss̄ > of pairs of strange valence quarks in final state hadrons in hadronic and nuclear collisions at CERNSPS energies are studied as a function of the mean number < ncoll > of nucleonnucleon collisions. Results give indications of an almost linear dependence over most of the region of < ncoll >. This in turn points out to strangeness b...
متن کاملEvent – by – event fluctuations in heavy – ion collisions and the quark – gluon string model
We apply dynamical string models of heavy–ions collisions at high energies to the analysis of event–by–event fluctuations. Main attention is devoted to a new variable proposed to study ”equilibration” in heavy–ions collisions. Recent results of the NA49 collaboration at CERN SPS are compared with predictions of the Quark–Gluon String Model (QGSM), which gives a good description of different asp...
متن کاملAGeV/c in Pb+Au Collisions
Abstract. Event-by-event fluctuations of mean pT and net charge in 40, 80, and 158 AGeV/c Pb+Au collisions are presented. The observed dynamical mean pT fluctuations in central events of about 1 % are very similar to results from RHIC. The centrality dependence of mean pT fluctuations at 158 AGeV/c shows a peculiar nonmonotonic pattern with respect to the extrapolation from the fluctuations mea...
متن کامل