STAR From the Spokesperson’s Perspective
By Nu Xu
Many years ago, I came to the U.S. as a graduate student from
the University of Science and Technology of China. I did my
Ph.D. degree at the State University of New York at Stony Brook
and then spent four years working on an experiment at the AGS.
Before I moved to Berkeley, I worked (with Professor Barbara
Jacak) at the Los Alamos National Lab for two and half years. I
joined the STAR Collaboration in 1997.
I think that we are in a very exciting period for Quantum-Chromodynamic (QCD) physics: RHIC is marching steadily towards the understanding of the properties of the strongly interacting medium produced in the high-energy nuclear collisions. At the same time, we are gaining tremendous insights into the structure of the proton from the RHIC spin program. Both PHENIX and STAR upgrades will further enhance our capability of detecting hadrons and leptons from heavy flavor decays. Both are essential penetrating probes for understanding early partonic dynamics. The RHIC energy scan program will allow us to map the QCD landscape and possibly determine the phase boundary. In addition, the commissioning of LHC will lead us to a new energy frontier where the properties of the initial states may be different from that discovered at RHIC.
RHIC has been a great success in science, in training the next generation young scientists, in building detectors, and in developing accelerator technology. We must maintain the momentum in order to achieve our scientific goals: understanding the medium properties at extremely high densities in heavy ion collisions and the origin of the nucleon spin through polarized p+p collisions. Note that the dynamic range of the density achieved in the collisions is very broad and, at different densities, the relevant degrees of freedom are different. Then the question is, can we understand these fundamental properties within the theoretical framework of QCD? What are the possible connections to the early universe? One of the most fascinating possibilities is that the span of the reached density may well be the defining factor of the phase boundary in the QCD landscape. The RHIC facilities allow us to explore all these exciting scientific frontiers.
I am grateful to be part of this great and exciting scientific endeavor.
The Relativistic Heavy Ion Collider at Brookhaven National
Laboratory is a world-class scientific research facility primarily
funded by the U.S. Department of Energy Office of Science. Hundreds
of physicists from around the world use RHIC to study what the
universe may have looked like in the first few moments after its
creation. What physicists learn from these collisions may help us
understand more about why the physical world works the way it does,
from the smallest subatomic particles, to the largest stars.