Quantifying the sQGP - Heavy Ion Collisions at RHIC

Abstract

This is the closeout for DE-FG02-86ER40271 entitled Quantifying the sQGP - Heavy Ion Collisions at the RHIC. Two major things were accomplished. The first, is the physics planning, design, approval, construction, and commissioning of the MPC-EX. The MPC-EX is an electromagnetic calorimeter covering a rapidity of 3<|eta|<4, which was added to the PHENIX detector. Its primary aim is to measure low-x gluons, in order to understand the suppression seen in a variety of signatures, such as the J/Psi. A candidate to explain this phenomena is the Color Glass Condensate (CGC) A second task was to look at collisions of asymmetric species, in particularly Cu+Au. The signature was the suppression of J/Psi mesons at forward and backward rapidity, where a stronger suppression was seen in the copper going direction. While the blue of the suppression is due to hot nuclear matter effects (e.g. screening) the increase in suppression on the Au side was consistent with cold nuclear matter effects seen in d+Au collisions. A major candidate for the explanation of this phenomena is the aforementioned CGC. Finally the work on sPHENIX, particularly an extension to the forward region, called fsPHENIX is described.