Abstract
Inclusive transverse momentum spectra of η mesons in the range –12 GeV/ have been measured at midrapidity () by the PHENIX experiment at RHIC in +Au, and Au+Au collisions at GeV. The η mesons are reconstructed through their channel for the three colliding systems as well as through the decay mode in and +Au collisions. The nuclear modification factor in +Au collisions, –1.1, suggests at most only modest broadening (“Cronin enhancement”). In central Au+Au reactions, the η yields are significantly suppressed, with . The ratio of η to yields is approximately constant as a function of for the three colliding systems in agreement with the high- world average of in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions for a wide range of center-of-mass energies (–1800 GeV) as well as, for high scaled momentum , in annihilations at GeV. These results are consistent with a scenario where high- η production in nuclear collisions at the Relativistic Heavy Ion Collider is largely unaffected by initial-state effects but where light-quark mesons () are equally suppressed due to final-state interactions of the parent partons in the dense medium produced in Au+Au reactions.
22 More- Received 6 November 2006
DOI:https://doi.org/10.1103/PhysRevC.75.024909
©2007 American Physical Society