Welcome to RHIC News
We hope that this web publication will in some small measure reflect the excitement of the RHIC and AGS program at Brookhaven, as explained by some of the people who are doing the experiments, analyzing the data, and writing the papers.
Photons at PHENIX
By Gabor David
Like a complicated movie plot, relativistic heavy ion collisions are a sequence and interplay of very different physics processes, which nevertheless strongly shape each others outcome - later ones often masking the effects of previous ones. We are reasonably certain that the main stages of this evolution are: modifications of the accelerated nucleus even before it collides, initial hard scattering of partons, formation and equilibration of a dense medium, its expansion, transformation and cooling, and formation of the final state (observable) particles. More...
Equation of State that Controls the Expansion of Matter Created
QCDOC and NYBlue Join Forces
By Frithjof Karsch
The expansion of hot and dense matter created in a heavy ion collision at RHIC is controlled by an equation of state which describes the dependence of the pressure in the medium on its energy density. Knowledge of the equation of state is, for instance, indispensable for a correct hydrodynamic modeling of the expansion of the transient form of matter created in a gold-gold collision at RHIC. More...
Diffractive Deep Inelastic Scattering Probes the QCD Vacuum
By Raju Venugopalan
Consider the following scenario: An electron slams into a proton at rest with an energy 50,000 times the proton rest energy and in about 1 in 7 such scatterings, nothing happens to the proton. In contrast, the virtual photon emitted by the scattered electron showers into a spray of hadrons separated in angle (or an equivalent unit called rapidity) from the proton. These striking diffractive events (see Fig. 1a) were observed in Deep Inelastic Scattering (DIS) experiments with the HERA collider at DESY, Germany. More...