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

Title: Proton-{Lambda} correlations in central Au+Au collisions at {radical}{ovr s}{sub NN} = 200 GeV.

Abstract

We report on p-{Lambda}, p-{bar {Lambda}}, {bar p}-{Lambda}, and {bar p}-{bar {Lambda}} correlation functions constructed in central Au-Au collisions at {radical}s{sub NN} = 200 GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p-{Lambda} and {bar p}-{bar {Lambda}} correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The p-{bar {Lambda}} and {bar p}-{Lambda} correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real part of the spin-averaged scattering length must be included in the final-state interactions calculation to reproduce the measured correlation function.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); National Science Foundation (NSF); Swiss NSF
OSTI Identifier:
966338
Report Number(s):
ANL-HEP-PR-09-66
Journal ID: ISSN 0556-2813; PRVCAN; TRN: US0903945
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. C; Journal Volume: 74; Journal Issue: 74 ; 2006
Country of Publication:
United States
Language:
ENGLISH
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANNIHILATION; CORRELATION FUNCTIONS; FINAL-STATE INTERACTIONS; PIONS; PROTONS; SCATTERING LENGTHS

Citation Formats

Cadman, R.V., Krueger, K., Spinka, H. M., McClain, C. J., Underwood, D. G., Adams, J., Aggarwal, M. M., Ahammed, Z., Amonett, J., Anderson, B. D., STAR Collaboration, High Energy Physics, Univ. of Birmingham, Panjab Univ., Variable Energy Cyclotron Centre, and Kent State Univ. Proton-{Lambda} correlations in central Au+Au collisions at {radical}{ovr s}{sub NN} = 200 GeV.. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.74.064906.
Cadman, R.V., Krueger, K., Spinka, H. M., McClain, C. J., Underwood, D. G., Adams, J., Aggarwal, M. M., Ahammed, Z., Amonett, J., Anderson, B. D., STAR Collaboration, High Energy Physics, Univ. of Birmingham, Panjab Univ., Variable Energy Cyclotron Centre, & Kent State Univ. Proton-{Lambda} correlations in central Au+Au collisions at {radical}{ovr s}{sub NN} = 200 GeV.. United States. doi:10.1103/PhysRevC.74.064906.
Cadman, R.V., Krueger, K., Spinka, H. M., McClain, C. J., Underwood, D. G., Adams, J., Aggarwal, M. M., Ahammed, Z., Amonett, J., Anderson, B. D., STAR Collaboration, High Energy Physics, Univ. of Birmingham, Panjab Univ., Variable Energy Cyclotron Centre, and Kent State Univ. Sun . "Proton-{Lambda} correlations in central Au+Au collisions at {radical}{ovr s}{sub NN} = 200 GeV.". United States. doi:10.1103/PhysRevC.74.064906.
@article{osti_966338,
title = {Proton-{Lambda} correlations in central Au+Au collisions at {radical}{ovr s}{sub NN} = 200 GeV.},
author = {Cadman, R.V. and Krueger, K. and Spinka, H. M. and McClain, C. J. and Underwood, D. G. and Adams, J. and Aggarwal, M. M. and Ahammed, Z. and Amonett, J. and Anderson, B. D. and STAR Collaboration and High Energy Physics and Univ. of Birmingham and Panjab Univ. and Variable Energy Cyclotron Centre and Kent State Univ.},
abstractNote = {We report on p-{Lambda}, p-{bar {Lambda}}, {bar p}-{Lambda}, and {bar p}-{bar {Lambda}} correlation functions constructed in central Au-Au collisions at {radical}s{sub NN} = 200 GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p-{Lambda} and {bar p}-{bar {Lambda}} correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The p-{bar {Lambda}} and {bar p}-{Lambda} correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real part of the spin-averaged scattering length must be included in the final-state interactions calculation to reproduce the measured correlation function.},
doi = {10.1103/PhysRevC.74.064906},
journal = {Phys. Rev. C},
number = 74 ; 2006,
volume = 74,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • We report on p-{lambda},p-{lambda},p-{lambda}, and p-{lambda} correlation functions constructed in central Au-Au collisions at {radical}(s{sub NN})=200 GeV by the STAR experiment at RHIC. The proton and lambda source size is inferred from the p-{lambda} and p-{lambda} correlation functions. It is found to be smaller than the pion source size also measured by the STAR experiment at smaller transverse masses, in agreement with a scenario of a strong universal collective flow. The p-{lambda} and p-{lambda} correlation functions, which are measured for the first time, exhibit a large anticorrelation. Annihilation channels and/or a negative real part of the spin-averaged scattering length mustmore » be included in the final-state interactions calculation to reproduce the measured correlation function.« less
  • Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at {radical}{ovr S{sub NN}}=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.
  • We report charged particle pair correlation analyses in the space of {Delta}{phi} (azimuth) and {Delta}{eta} (pseudorapidity), for central Au+Au collisions at {radical}s{sub NN} = 200 GeV in the STAR detector. The analysis involves unlike-sign charged pairs and like-sign charged pairs, which are transformed into charge-dependent (CD) signals and charge-independent (CI) signals. We present detailed parametrizations of the data. A model featuring dense gluonic hot spots as first proposed by Van Hove predicts that the observables under investigation would have sensitivity to such a substructure should it occur, and the model also motivates selection of transverse momenta in the range 0.8more » < p{sub T} < 2.0 GeV/c. Both CD and CI correlations of high statistical significance are observed, and possible interpretations are discussed.« less
  • We present first measurements of the pseudorapidity and azimuth ({eta}, {phi}) bin-size dependence of event-wise mean transverse-momentum <p{sub T}> fluctuations for Au-Au collisions at {radical}s{sub NN} = 200 GeV. We invert that dependence to obtain p{sub t} autocorrelations on differences ({eta}{sub {Delta}}, {phi}{sub {Delta}}) interpreted to represent velocity/temperature distributions on ({eta}, {phi}). The general form of the autocorrelations suggests that the basic correlation mechanism is parton fragmentation. The autocorrelations vary rapidly with collision centrality, which suggests that fragmentation is strongly modified by a dissipative medium in the more central Au-Au collisions relative to peripheral or p-p collisions.
  • Forward-backward multiplicity correlation strengths have been measured with the STAR detector for Au+Au and p+p collisions at {radical}s{sub NN} = 200 GeV. Strong short- and long-range correlations (LRC) are seen in central Au+Au collisions. The magnitude of these correlations decrease with decreasing centrality until only short-range correlations are observed in peripheral Au+Au collisions. Both the dual parton model (DPM) and the color glass condensate (CGC) predict the existence of the long-range correlations. In the DPM, the fluctuation in the number of elementary (parton) inelastic collisions produces the LRC. In the CGC, longitudinal color flux tubes generate the LRC. The datamore » are in qualitative agreement with the predictions of the DPM and indicate the presence of multiple parton interactions.« less