Correlated production of p and p¯ source in Au + Au collisions at √sNN=200 GeV

Andrew Adare, University of Colorado, Boulder
Sergey Belikov, Iowa State University
Paul Constantin, Iowa State University
Nathan C. Grau, Iowa State University
John C. Hill, Iowa State University
John G. Lajoie, Iowa State University
Alexandre Lebedev, Iowa State University
Craig Ogilvie, Iowa State University
H. Pei, Iowa State University
Jan Rak, Iowa State University
Marzia Rosati, Iowa State University
Carla Vale, Iowa State University
et al.

This article is from Physics Letters B 649 (2007): 359, doi:10.1016/j.physletb.2007.04.029. Posted with permission.

Abstract

Correlations between p and p¯ at transverse momenta typical of enhanced baryon production in Au + Au collisions are reported. The PHENIX experiment has measured same and opposite sign baryon pairs in Au + Au collisions at √sNN=200 GeV. Correlated production of p and p¯ with the trigger particle from the range 2.5 < pT < 4.0 GeV/c and the associated particle with 1.8 < pT < 2.5 GeV/c is observed to be nearly independent of the centrality of the collisions. Same sign pairs show no correlation at any centrality. The conditional yield of mesons triggered by baryons (and anti-baryons) and mesons in the same pT range rises with increasing centrality, except for the most central collisions, where baryons show a significantly smaller number of associated mesons. These data are consistent with a picture in which hard scattered partons produce correlated p and p¯ in the pT region of the baryon excess.