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Douglas
L. Olson, Ernest Orlando Lawrence Berkeley National Laboratory
John Harris, Yale University
Research
Objectives
The STAR detector (Solenoidal Tracker at RHIC) at Brookhaven National
Laboratory is a large acceptance collider detector designed to study the
collision of heavy nuclei at very high energy in the laboratory. Its goal
is to investigate nuclear matter at extreme energy density and to search
for evidence of the phase transition between hadronic matter and the deconfined
quark-gluon plasma (QGP). STAR and the RHIC accelerator began operation
in June 2000. The complete STAR detector will contain a set of time projection
chambers for charged particle tracking, a silicon detector for vertexing,
electromagnetic calorimeters, and a number of other systems.
Computational
Approach
The basic method of deriving physics results in experimental relativistic
heavy ion collisions is to carry out statistical analysis of large numbers
of events (collisions of individual atomic nuclei). The theoretical models
are implemented as Monte Carlo codes that describe the final state of
each of the thousands of particles that are produced in these collisions.
We use a number of these theoretical codes (VENUS, HIJING, RQMD, and others)
to produce large samples of events. A simulation code called GEANT is
used to propagate each of these thousands of particles through the material
of the STAR detector and compute the reactions and energy deposition that
occurs throughout the detector. These theoretical model codes and the
detector simulation code are run on MPP systems utilizing the natural
parallelism of the problem, namely that each event is independent, so
that different events are computed in parallel on the various processor
nodes.
Accomplishments
In FY 2000 STAR detector simulations were
run on the T3E with both the VENUS and HIJING event
generators in various configurations of impact parameters
and physics conditions, all for the detector configuration
that STAR is presently running with at RHIC. In total
(as of July 2000) we produced 26K events of Au +
Au collisions with about 1.5 TB total volume.
Significance
The existence of the QGP is predicted by lattice QCD calculations, and
this state of matter is thought to be important in the dynamics of the
early universe and the core of neutron stars. The most violent nuclear
collisions at RHIC will generate approximately 10 thousand secondary particles.
STAR aims to detect and characterize a large fraction of these secondaries
in order to reconstruct a meaningful picture of each individual collision.
Publications
D. Hardtke (for the STAR Collaboration), "Inclusive particle spectra and
exotic particle searches using STAR," in Proceedings of ISMD99
(Brown University, Rhode Island, Aug. 9—13, 1999).
H.
Caines (for the STAR Collaboration), "The year-one physics capabilities
of STAR," in Proceedings of the Relativistic Heavy Ion Mini-Symposium
at the APS Centennial Meeting (Atlanta, GA, March 21—26, 1999).
W.
B. Christie, "Data sets for high pT physics with the STAR detector," in
Proceedings of Hard Parton Physics in High Energy Nuclear Collisions
Workshop (Brookhaven National Laboratory, Upton, NY, March 1—5,
1999); report No. BNL-52574.
http://www.star.bnl.gov/
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