Recent Results from RHIC & Some Lessons for Cosmic-Ray Physicists

Abstract

The Relativistic Heavy Ion Collider (RHIC) studies nuclear matter under a variety of conditions. Cold nuclear matter is probed with deuteron-gold collisions, while hot nuclear matter(possibly a quark-gluon plasma (QGP)) is created in heavy-ion collisions. The distribution of spin in polarized nucleons is measured with polarized proton collisions, and photoproduction is studied using the photons that accompany heavy nuclei. The deuteron-gold data shows less forward particle production than would be expected from a superposition of $pp$ collisions, as expected due to saturation/shadowing. Particle production in $AA$ collisions is well described by a model of an expanding fireball in thermal equilibrium. Strong hydrodynamic flow and jet quenching shows that the the produced matter interacts very strongly. These phenomena are consistent with new non-perturbative interactions near the transition temperature to the QGP. This writeup will discuss these results, and their implications for cosmic-ray physicists.

8 pgs; invited talk presented at the XIVth International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2006)

References in corpus (3)

• Common Suppression Pattern of eta and pi^0 Mesons at High Transverse Momentum in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• Forward Neutral Pion Production in p+p and d+Au Collisions at sqrt(s_NN)=200 GeV
• Improved Measurement of Double Helicity Asymmetry in Inclusive Midrapidity pi^0 Production for Polarized p+p Collisions at sqrt(s)=200 GeV