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

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

The new generation of ultrarelativistic heavy ion colliders, RHIC at Brookhaven and LHC at CERN will open a window to the Early Universe when it was one microsecond old. In these experiments a new state of matter-the quark gluon plasma- will be formed. This state prevailed when the Universe was younger than a microsecond with temperatures larger than 1012 K. This novel state is also conjectured to exist at the core of the densest stars in the Universe-neutron stars- and to be the primary constituent of hypothetical quark stars. The density in these astrophysical objects is about 1015gr/cc, these stars are the remnant of the most powerful events in the present Universesupernovae explosions. The properties of neutron stars and the existence of quark stars is currently being studied by a host of satellite missions: HST, Rosat, Chandra, XMM-Newton and forthcoming neutrino telescopes. Assessing potential observables and experimental signatures of the quark gluon plasma requires studying 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 transient state with an unprecedented short lifetime of the order of 10-22 seconds, undergoing a phase transition to a phase in which quarks and gluons are con.ned inside hadrons. Thus the challenge is to extract observational signatures fromthe short-lived and rapidly evolving plasma. The focus and goal of this proposal is to implement the methods that we developed during the last several years to study equilibriumand non-equilibriumexp erimental signatures of the quark gluon plasma and the phase transitions in ultrarelativistic heavy ion collisions and in compact stars. In particular we focus on: i) electromagnetic signatures (photons and lepton pairs), ii) transport phenomena and properties of .uctuations as potential observables of the phase transitions, iii) astrophysical processes that lead to observational signals of quark matter in strongly magnetized neutron stars and quark stars: photon and neutrino emissions. Intellectual challenge: This is a truly interdisciplinary programat the forefront of nuclear and particle physics and astrophysics and cosmology. Many of the methods, in particular transport phenomena strongly out of equilibrium also overlaps with timely problems in condensed matter physics: femtosecond relaxation in semiconductors. Thus we expect that the program will also have a broad impact in many areas. The possibility of opening a window to the Early Universe with earth-bound accelerators and studying the densest stars, the remnants of the most energetic events 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 exotic objects in the present Universe goes beyond the scientists working in these areas, and reaches to the broad audience. The general public is fascinated about the latest discoveries in cosmology and particle physics, and eager to listen and learn more. The symbiosis between cosmology, astrophysics and nuclear and particle physics lends itself to being an e.ective vehicle to transmit the new and fascinating discoveries and to highlight the importance of the di.erent areas to unravel the ultimate mysteries of the Universe. The projects described in this proposal are a continuation of the research done under the previous Grant: N.S.F. PHY-9988720 (5/31/00-5/31/03) and is estimated for a period of three years.