Relativistic Heavy-Ion Physics at the University of Rochester

University Of Rochester, Rochester NY

Investigators

Abstract

This grant provides operating funds for the relativistic heavy-ion group at the Department of Physics and Astronomy at the University of Rochester. During the year covered by this grant we will complete the analysis of the data collected in 2001 and 2003 with the PHOBOS detector at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) and consider possible upgrade options for the PHOBOS detector. PHOBOS is one of the four experiments looking at the extreme energy densities that are created when nuclei collide at RHIC. It is believed that a new state of matter, the so-called quark-gluon plasma (QGP), will be formed in these collisions. PHOBOS is looking for this new state of matter, and its properties will provide important and new information about the state of the very early universe (a few microseconds after the Big Bang). PHOBOS was designed to study as many collisions as possible, in an unbiased way, and to search for significant differences between p+p, p+A, and A+A collisions. The data collected sofar inlcudes studies of Au+Au collisions in 2001, d+Au in 2003, and p+p in 2001 and 2003. It is expected that the QGP will only be formed in the Au+Au collisions, and the studies of d+Au and p+p are used to subtract the contribution of "normal" nucleon-nucleon physics from the data collected in Au+Au collisions. The time-of-flight array, designed and constructed by the Rochester group, significantly enhances the physics capabilities of PHOBOS, by roughly doubling its particle identification capabilities. For the 2003 run we have increased the flight path of our arrays, allowing use to identify particles up to momenta of around 4 - 5 GeV/c. The analysis of the 2001 data is almost completed, and the analysis of the 2003 data is just getting started.