skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Multiplicity and pseudorapidity distributions of charged particles and photons at forward pseudorapidity in Au+Au collisons at {radical}(s{sub NN})=62.4 GeV

Abstract

We present the centrality-dependent measurement of multiplicity and pseudorapidity distributions of charged particles and photons in Au+Au collisions at {radical}(s{sub NN})=62.4 GeV. The charged particles and photons are measured in the pseudorapidity region 2.9{<=}{eta}{<=}3.9 and 2.3{<=}{eta}{<=}3.7, respectively. We have studied the scaling of particle production with the number of participating nucleons and the number of binary collisions. The photon and charged particle production in the measured pseudorapidity range has been shown to be consistent with energy-independent limiting fragmentation behavior. Photons are observed to follow a centrality-independent limiting fragmentation behavior, while for charged particles it is centrality dependent. We have carried out a comparative study of the pseudorapidity distributions of positively charged hadrons, negatively charged hadrons, photons, pions, and net protons in nucleus-nucleus collisions and pseudorapidity distributions from p+p collisions. From these comparisons, we conclude that baryons in the inclusive charged particle distribution are responsible for the observed centrality dependence of limiting fragmentation. The mesons are found to follow an energy-independent behavior of limiting fragmentation, whereas the behavior of baryons is energy dependent.

Authors:
; ; ; ; ; ;  [1]; ; ; ;  [2]; ; ; ; ; ; ; ; ;  [3]
  1. University of Birmingham, Birmingham (United Kingdom)
  2. Panjab University, Chandigarh 160014 (India)
  3. Variable Energy Cyclotron Centre, Kolkata 700064 (India) (and others)
Publication Date:
OSTI Identifier:
20771367
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.73.034906; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; CHARGED PARTICLES; COMPARATIVE EVALUATIONS; DISTRIBUTION; ENERGY DEPENDENCE; GEV RANGE; GOLD 197 REACTIONS; GOLD 197 TARGET; LIMITING FRAGMENTATION; MULTIPLICITY; PARTICLE PRODUCTION; PARTICLE RAPIDITY; PHOTONS; PIONS; PROTONS

Citation Formats

Adams, J., Barnby, L.S., Blyth, C.O., Gaillard, L., Jones, P.G., Nelson, J.M., Timmins, A.R., Aggarwal, M.M., Bhati, A.K., Kumar, A., Sharma, M., Ahammed, Z., Chattopadhyay, S., Das, D., Das, S., Majumdar, M.R. Dutta, Ganti, M.S., Ghosh, P., Mohanty, B., and Nayak, T.K. Multiplicity and pseudorapidity distributions of charged particles and photons at forward pseudorapidity in Au+Au collisons at {radical}(s{sub NN})=62.4 GeV. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.034906.
Adams, J., Barnby, L.S., Blyth, C.O., Gaillard, L., Jones, P.G., Nelson, J.M., Timmins, A.R., Aggarwal, M.M., Bhati, A.K., Kumar, A., Sharma, M., Ahammed, Z., Chattopadhyay, S., Das, D., Das, S., Majumdar, M.R. Dutta, Ganti, M.S., Ghosh, P., Mohanty, B., & Nayak, T.K. Multiplicity and pseudorapidity distributions of charged particles and photons at forward pseudorapidity in Au+Au collisons at {radical}(s{sub NN})=62.4 GeV. United States. doi:10.1103/PhysRevC.73.034906.
Adams, J., Barnby, L.S., Blyth, C.O., Gaillard, L., Jones, P.G., Nelson, J.M., Timmins, A.R., Aggarwal, M.M., Bhati, A.K., Kumar, A., Sharma, M., Ahammed, Z., Chattopadhyay, S., Das, D., Das, S., Majumdar, M.R. Dutta, Ganti, M.S., Ghosh, P., Mohanty, B., and Nayak, T.K. Wed . "Multiplicity and pseudorapidity distributions of charged particles and photons at forward pseudorapidity in Au+Au collisons at {radical}(s{sub NN})=62.4 GeV". United States. doi:10.1103/PhysRevC.73.034906.
@article{osti_20771367,
title = {Multiplicity and pseudorapidity distributions of charged particles and photons at forward pseudorapidity in Au+Au collisons at {radical}(s{sub NN})=62.4 GeV},
author = {Adams, J. and Barnby, L.S. and Blyth, C.O. and Gaillard, L. and Jones, P.G. and Nelson, J.M. and Timmins, A.R. and Aggarwal, M.M. and Bhati, A.K. and Kumar, A. and Sharma, M. and Ahammed, Z. and Chattopadhyay, S. and Das, D. and Das, S. and Majumdar, M.R. Dutta and Ganti, M.S. and Ghosh, P. and Mohanty, B. and Nayak, T.K.},
abstractNote = {We present the centrality-dependent measurement of multiplicity and pseudorapidity distributions of charged particles and photons in Au+Au collisions at {radical}(s{sub NN})=62.4 GeV. The charged particles and photons are measured in the pseudorapidity region 2.9{<=}{eta}{<=}3.9 and 2.3{<=}{eta}{<=}3.7, respectively. We have studied the scaling of particle production with the number of participating nucleons and the number of binary collisions. The photon and charged particle production in the measured pseudorapidity range has been shown to be consistent with energy-independent limiting fragmentation behavior. Photons are observed to follow a centrality-independent limiting fragmentation behavior, while for charged particles it is centrality dependent. We have carried out a comparative study of the pseudorapidity distributions of positively charged hadrons, negatively charged hadrons, photons, pions, and net protons in nucleus-nucleus collisions and pseudorapidity distributions from p+p collisions. From these comparisons, we conclude that baryons in the inclusive charged particle distribution are responsible for the observed centrality dependence of limiting fragmentation. The mesons are found to follow an energy-independent behavior of limiting fragmentation, whereas the behavior of baryons is energy dependent.},
doi = {10.1103/PhysRevC.73.034906},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • We present the first measurement of pseudorapidity distribution of photons in the region 2.3{<=}{eta}{<=}3.7 for different centralities in Au+Au collisions at {radical}(s{sub NN})=62.4 GeV. We find that the photon yield scales with the number of participating nucleons at all collision centralities studied. The pseudorapidity distribution of photons, dominated by {pi}{sup 0} decays, has been compared to those of charged pions, photons, and inclusive charged particles from heavy-ion and nucleon-nucleon collisions at various energies. The photon production has been shown to be consistent with the energy and centrality independent limiting fragmentation scenario.
  • The charged-particle pseudorapidity density for Au+Au collisions at {radical}(s{sub NN})=62.4 GeV has been measured over a wide range of impact parameters and compared to results obtained at other energies. As a function of collision energy, the pseudorapidity distribution grows systematically both in height and width. The midrapidity density is found to grow approximately logarithmically between BNL Alternating Gradient Synchrotron (AGS) energies and the top BNL Relativistic Heavy Ion Collider (RHIC) energy. There is also an approximate factorization of the centrality and energy dependence of the midrapidity yields. The new results at {radical}(s{sub NN})=62.4 GeV confirm the previously observed phenomenon ofmore » ''extended longitudinal scaling'' in the pseudorapidity distributions when viewed in the rest frame of one of the colliding nuclei. It is also found that the evolution of the shape of the distribution with centrality is energy independent, when viewed in this reference frame. As a function of centrality, the total charged particle multiplicity scales linearly with the number of participant pairs as it was observed at other energies.« less
  • Longitudinal density correlations of produced matter in Au+Au collisions at {radical}(s{sub NN})=200 GeV have been measured from the inclusive charged particle distributions as a function of pseudorapidity window sizes. The extracted {alpha}{xi} parameter, related to the susceptibility of the density fluctuations in the long-wavelength limit, exhibits a nonmonotonic behavior as a function of the number of participant nucleons, N{sub part}. A local maximum is seen at N{sub part}{approx}90, with corresponding energy density based on the Bjorken picture of {epsilon}{sub Bj}{tau}{approx}2.4 GeV/(fm{sup 2}c) with a transverse area size of 60 fm{sup 2}. This behavior may suggest a critical phase boundary basedmore » on the Ginzburg-Landau framework.« less
  • No abstract prepared.
  • Longitudinal density correlations of produced matter in Au+Au collisions at sqrt(s{sub NN})=200 GeV have been measured from the inclusive charged particle distributions as a function of pseudorapidity window sizes. The extracted {alpha}{xi} parameter, related to the susceptibility of the density fluctuations in the long-wavelength limit, exhibits a nonmonotonic behavior as a function of the number of participant nucleons, N{sub part}. A local maximum is seen at N{sub part}{approx}90, with corresponding energy density based on the Bjorken picture of {epsilon}{sub Bj}{tau}{approx}2.4 GeV/(fm{sup 2}c) with a transverse area size of 60 fm2. This behavior may suggest a critical phase boundary based onmore » the Ginzburg-Landau framework.« less