Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userEnergy and rapidity dependence of electric charge correlations at 20-158GeV beam energies at the CERN SPS (NA49)
241
0
0.0
(
0
)
Authors
NA49 Collaboration
Ask ChatGPT about the research
No Arabic abstract
Electric charge correlations are studied with the Balance Function method for central Pb + Pb collisions at the CERN - SPS. The results on centrality selected Pb + Pb interactions at 40 and 158 AGeV are presented for the first time for two different rapidity intervals. In the mid-rapidity region a decrease of the width with increasing centrality of the collision is observed whereas in the forward rapidity region this effect vanishes. This could suggest a delayed hadronization scenario. In addition, the results from a first attempt to study the energy dependence of the Balance Function throughout the whole SPS energy range, are presented. The suitably scaled decrease of the width is approximately constant for the intermediate energies (30 to 80 AGeV) and gets stronger for the highest SPS and RHIC energies. On the other hand, both URQMD and HSD simulation results show no dependence on the collision energy.
rate research
Read More
Results from electric charge correlations studied with the Balance Function method in A+A collisions from 20emph{A} to 158emph{A} GeV are presented in two different rapidity intervals: In the mid-rapidity region we observe a decrease of the width of the Balance Function distribution with increasing centrality of the collision, whereas this effect vanishes in the forward rapidity region. Results from the energy dependence study in central Pb+Pb collisions show that the narrowing of the Balance Function expressed by the normalised width parameter textit{W} increases with energy towards the highest SPS and RHIC energies. Finally we compare our experimental data points with predictions of several models. The hadronic string models UrQMD and HIJING do not reproduce the observed narrowing of the Balance Function. However, AMPT which contains a quark-parton transport phase before hadronization can reproduce the narrowing of the BFs width with centrality. This confirms the proposed sensitivity of the Balance Function analysis to the time of hadronization.
Results are presented of a two-pion interferometry (HBT) analysis in Pb+Au collisions at 40, 80, and 158 AGeV. A detailed study of the Bertsch-Pratt HBT radius parameters has been performed as function of the mean pair transverse momentum $k_t$ and in bins of the centrality of the collision. From these results we extract model dependent information about the space-time evolution of the reaction. An investigation of the effective volume of the pion emitting system provides an important tool to study the properties of thermal pion freeze-out.
The Balance Function analysis method was developed in order to study the long range correlations in pseudo-rapidity of charged particle. The final results on p+p, C+C, Si+Si and centrality selected Pb+Pb collisions at $sqrt{s_{NN}} = 17.2$ GeV and the preliminary data at $sqrt{s_{NN}} = 8.8$ GeV are presented. The width of the Balance Function decreases with increasing system size and centrality of the collisions. This could suggest a delayed hadronization scenario.
Two-particle azimuthal correlations of high-pT hadrons can serve as a probe of interactions of partons with the dense medium produced in high-energy heavy-ion collisions. First NA49 results on such correlations are presented for central and mid-central Pb+Pb collisions at 158A GeV beam energy, for different centrality bins and charge combinations of trigger and associate particles. These results feature a flattened away-side peak in the most central collisions, which is consistent with expectations of the medium-interaction scenario. A comparison with CERES Pb+Au results at the same energy, as well as with PHENIX Au+Au results at the top RHIC energy, is provided.
A new heavy-ion experiment on fixed target, NA60+, has been proposed at the CERN SPS for data taking in the next years. Its main goals will be focused on precision studies of thermal dimuons, heavy quark and strangeness production in Pb-Pb collisions at center-of-mass energies ranging from 5 to 17 GeV, which will provide a unique opportunity to investigate the region of the QCD phase diagram at high baryochemical potential ($mu_B sim 200-400$~MeV). The key points of the NA60+ very broad and ambitious physics program will be described.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
