Elucidating Jet Quenching and Medium Response Mechanisms via Hard Probes in Relativistic Heavy-ion Collisions

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At extremely high temperature and density, the normal nuclear matter we experience every day "melts'" into the so called Quark-gluon plasma (QGP) phase consisting of "quasi-free'" quarks and gluons, a phase believed to have existed during the first 10 microseconds after our universe was born in the Big Bang. This QGP can be created by heating matter above a temperature of 170 millon electron volts. Experimentally, this is done by colliding two large nuclei (typically Gold or Lead) at very high energy. The resulting hot and dense fireball is expected to expand under its own pressure, and cool down. Properties of the QGP such as its temperature, pressure, chemical potential, viscosity, diffusion coefficient, speed of sound, etc. can be deduced from thousands of particles emitted from the fireball and detected with large scale particle detectors surrounding the interaction region. Such studies are being carried out in the PHENIX experiment at the Relativistic Heavy-ion Collider (RHIC) and planned for the ATLAS experiment at the Large Hadron Collider (LHC), respectively. This project is focused on a set of exclusive measurements that can establish the properties of the high-density matter created at RHIC via the PHENIX detector, as well as applying some of these measurement techniques at LHC using the ATLAS detector. Specifically, we will probe the properties of this matter via measurements of high-energy single jets and back-to-back jet pairs (di-jets). The research will improve our present understanding of the fundamental nature of the matter under extreme conditions, and therefore has a broad impact on other fields of endeavor such as astrophysics and super-string theories. Participation by graduate students and undergraduate students is expected throughout the program. The PHENIX experiment provide a diverse array of research topics at all levels of education, as well as an excellent working environment involving interactions between hundreds of scientists in the field, and unique opportunities for career development in programming, hardware, leadership and academics.