WELCOME TO RELATIVISTIC HEAVY ION PHYSICS GROUP

The Quark Gluon Plasma (QGP) is a state of matter heated to to such a high temperature (1 trillion K) that nuclei melt into a soup of quasi-free quarks and gluons.The group at UCR has played a major role in the discovery of the Quark Gluon Plasma. Surprisingly it had very different properties than was originally expected. It was a near "perfect" liquid, with a minimal viscosity to entropy ratio. The task is now to study the QGP, in particular to identify the 1st order phase transition line and the critical point. We have recently joined the STAR experiment to answer these questions. The end-on view of the detector is shown in the photograph. The previous page shows the explosion of a QGP as seen by STAR.

THE QUARK GLUON PLASMA

and the

STAR EXPERIMENT AT BNL

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Relativistic Heavy Ion Collisions

Anatomy of a collision: The bottom panel shows a cartoon of the collision of a pair of gold nuclei at 200 GeV center of mass energy. The top panel indicates the state of the system.

The incoming nuclei are pancakes in the lab frame because of Lorenz contraction.
Upon collision the initial energy density is very high and the system is in a pre-equilibrium state
At about a time of 1 about fm/c, the system equilibrates to a Quark Gluon Plasma with a temperature of kT~150 MeV
The system then cools and below the phase transition temperature and the system freezes out into mesons and baryons which are detected by STAR

RICHARD SETO

I grew up in a small town south of Seattle, and then left the green forests and majestic mountains of the Pacific Northwest for the east coast to go to college. (It was the first time I few in a airplane!) After I got my Ph.D. in high energy physics, I came to UCR and switched into the field of Relativistic Heavy Ions, where I became the spokesperson of Experiment 917 at the Brookhaven National Lab. After the Relativistic Heavy Ion Collider began operations, I joined the PHENIX experiment where I spent several exciting years as we found the Quark Gluon Plasma (QGP), a state of matter in which quarks and gluons are melted into a hot fiery ball. I have now joined the STAR experiment where we plan to study the phase transition line between heavy nuclei and the QGP, a phase transition governed by the strong interaction.

my email: richard.seto@ucr.edu my office: 3029 physics, the best way to reach me is by email, or just drop by

The group is looking for graduate students - so if you are interested, contact me.

Exploring the phase transition line

So far, we have studied the QGP, primarily at high energies where the trajectory of the collision passes through a "cross over", as is indicated by the 200 GeV line on the left i.e. not a 1st order phase transition. (The transition between liquid and steam is 1st order). In the next two years STAR plans to do a beam energy scan between about 3.0 and 19.6 GeV center of mass energies to locate the 1st order transition line and the critical point.

My Papers