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Title: Energy and rapidity dependence of the electric charge correlations at 20-158GeV beam energies at the CERN SPS (NA49)

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: The mid-rapidity region where a decrease of the width with increasing centrality of the collision is observed and the forward rapidity region where 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, will also be 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.

Authors:
; ;  [1]
  1. Physics Department - University of Athens -15771 - Athens (Greece)
Publication Date:
OSTI Identifier:
20800063
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 828; Journal Issue: 1; Conference: 35. internationals symposium on multiparticle dynamics; Workshop on particle correlations and femtoscopy, Kromeriz (Czech Republic), 9-17 Aug 2005; Other Information: DOI: 10.1063/1.2197403; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BROOKHAVEN RHIC; CERN SPS SYNCHROTRON; COMPUTERIZED SIMULATION; CORRELATIONS; ELECTRIC CHARGES; ENERGY DEPENDENCE; GEV RANGE; LEAD 208 REACTIONS; LEAD 208 TARGET; MOLECULAR DYNAMICS METHOD; PARTICLE RAPIDITY

Citation Formats

Christakoglou, P., Petridis, A., and Vassiliou, M.. Energy and rapidity dependence of the electric charge correlations at 20-158GeV beam energies at the CERN SPS (NA49). United States: N. p., 2006. Web. doi:10.1063/1.2197403.
Christakoglou, P., Petridis, A., & Vassiliou, M.. Energy and rapidity dependence of the electric charge correlations at 20-158GeV beam energies at the CERN SPS (NA49). United States. doi:10.1063/1.2197403.
Christakoglou, P., Petridis, A., and Vassiliou, M.. Tue . "Energy and rapidity dependence of the electric charge correlations at 20-158GeV beam energies at the CERN SPS (NA49)". United States. doi:10.1063/1.2197403.
@article{osti_20800063,
title = {Energy and rapidity dependence of the electric charge correlations at 20-158GeV beam energies at the CERN SPS (NA49)},
author = {Christakoglou, P. and Petridis, A. and Vassiliou, M.},
abstractNote = {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: The mid-rapidity region where a decrease of the width with increasing centrality of the collision is observed and the forward rapidity region where 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, will also be 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.},
doi = {10.1063/1.2197403},
journal = {AIP Conference Proceedings},
number = 1,
volume = 828,
place = {United States},
year = {Tue Apr 11 00:00:00 EDT 2006},
month = {Tue Apr 11 00:00:00 EDT 2006}
}
  • This article is devoted to results on {pi}-{pi}--Bose-Einstein correlations in central Pb+Pb collisions measured by the NA49 experiment at the CERN SPS. Rapidity as well as transverse momentum dependences of the correlation lengths will be shown for collisions at 20A, 30A, 40A, 80A, and 158A GeV beam energy. Only a weak energy dependence of the radii is observed at SPS energies. The kt-dependence of the correlation lengths as well as the single particle mt-spectra will be compared to model calculations. The rapidity dependence is analysed in a range of 2.5 units of rapidity starting at the center of mass rapiditymore » at each beam energy. The correlation lengths measured in the longitudinally comoving system show only a weak dependence on rapidity.« less
  • Results from electric charge correlations studied with the Balance Function (BF) method in A+A collisions from 20A to 158A GeV are presented in two different rapidity intervals: In the midrapidity region we observe a decrease of the width of the BF 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 BF expressed by the normalized width parameter W increases with energy toward the highest CERN Super Proton Synchrotron and BNL Relativistic Heavy Ion Collider energies. Finally wemore » compare our experimental data points with the predictions of several models. The hadronic string models Ultra-relativistic Quantum Molecular Dynamics and Heavy Ion Jet INteraction Generator (HIJING) do not reproduce the observed narrowing of the BF. However, A MultiPhase Transport medel (AMPT), which contains a quark-parton transport phase before hadronization, can reproduce the narrowing of the BF's width with centrality. This confirms the proposed sensitivity of the BF analysis to the time of hadronization.« less
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  • In this paper measurements are presented of short range three-particle rapidity correlations in pp interactions at c.m. energies {radical} s = 31, 44 and 62 GeV. The data were obtained at the CERN Intersecting Storage Rings (ISR) using the split Field Magnet Detector (SFM) with a minimum bias trigger. Three-particle short range rapidity correlations are observed for the ({minus}+{minus}) and (+{minus}+) combinations; no short-range rapidity correlation is observed for the ({minus}{minus}{minus}) and (+++) configurations. The rapidity range of the three-particle correlations is approximately the same as for the two-particle correlations.
  • NA49 is a major new experimental facility at the CERN SPS designed for the study of Lead-Lead collisions at ultrarelativistic energies. The main components of NA49 are four large Time Projection Chambers (TPCs) situated inside and downstream of two dipole magnets for the momentum analysis and identification of all (meta)stable hadrons in the forward half of phase space. Two of the four TPCs were brought into operation during the first Lead Beam run at the CERN SPS in November 1994. The author presents the first physics results from the TPCs for central and minimum bias Lead-Lead collisions at 160 GeV/nucleon.