Equilibrium and Nonequilibrium Signatures of the Quark Gluon Plasma at High Temperature and Density

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The new generation of ultrarelativistic heavy ion colliders, RHIC at Brookhaven and LHC at CERNwill open a window to the Early Universe when it was one microsecond old. In these experimentsa new state of matter-the quark gluon plasma- will be formed. This state prevailed when theUniverse was younger than a microsecond with temperatures larger than 1012 K. This novel stateis also conjectured to exist at the core of the densest stars in the Universe-neutron stars- and to bethe primary constituent of hypothetical quark stars. The density in these astrophysical objects isabout 1015gr/cc, these stars are the remnant of the most powerful events in the present Universesupernovaeexplosions. The properties of neutron stars and the existence of quark stars is currentlybeing studied by a host of satellite missions: HST, Rosat, Chandra, XMM-Newton and forthcomingneutrino telescopes.Assessing potential observables and experimental signatures of the quark gluon plasma requiresstudying the strong interactions in an unprecedented regime of temperatures and densities. Furthermore,in ultrarelativistic heavy ion collisions the quark gluon plasma is expected to be a transientstate with an unprecedented short lifetime of the order of 10-22 seconds, undergoing a phase transitionto a phase in which quarks and gluons are con.ned inside hadrons. Thus the challenge is toextract observational signatures fromthe short-lived and rapidly evolving plasma. The focus andgoal of this proposal is to implement the methods that we developed during the last several yearsto study equilibriumand non-equilibriumexp erimental signatures of the quark gluon plasma andthe phase transitions in ultrarelativistic heavy ion collisions and in compact stars. In particularwe focus on: i) electromagnetic signatures (photons and lepton pairs), ii) transport phenomenaand properties of .uctuations as potential observables of the phase transitions, iii) astrophysicalprocesses that lead to observational signals of quark matter in strongly magnetized neutron starsand quark stars: photon and neutrino emissions.Intellectual challenge: This is a truly interdisciplinary programat the forefront of nuclearand particle physics and astrophysics and cosmology. Many of the methods, in particular transportphenomena strongly out of equilibrium also overlaps with timely problems in condensed matterphysics: femtosecond relaxation in semiconductors. Thus we expect that the program will alsohave a broad impact in many areas. The possibility of opening a window to the Early Universewith earth-bound accelerators and studying the densest stars, the remnants of the most energeticevents in the Universe-Supernovae explosions-is clearly one of the most fascinating endeavors.Broad interest: The appeal of studying the Early Universe and some of the most exoticobjects in the present Universe goes beyond the scientists working in these areas, and reaches tothe broad audience. The general public is fascinated about the latest discoveries in cosmology andparticle physics, and eager to listen and learn more. The symbiosis between cosmology, astrophysicsand nuclear and particle physics lends itself to being an e.ective vehicle to transmit the new andfascinating discoveries and to highlight the importance of the di.erent areas to unravel the ultimatemysteries of the Universe.The projects described in this proposal are a continuation of the research done under theprevious Grant: N.S.F. PHY-9988720 (5/31/00-5/31/03) and is estimated for a period of threeyears.