We will perform several measurements that can establish the properties of the high energy density matter created in relativistic heavy ion collisions at both the Relativistic Heavy ion Collider (RHIC) at BNL and the Large Hadron Collider (LHC) at CERN. Specifically, we will probe the properties of this matter by studying the collective flow and jet quenching phenomena. In earlier work, we have shown that this matter not only exhibits significant harmonic flows of many orders arising from the density fluctuations in the initial collision geometry, but also exhibits strong jet-medium interactions as well as a response of the medium to the quenched jets. Our future efforts will be aimed at establishing a more quantitative understanding of the microscopic mechanisms for the flow and and jet-medium interactions. We plan to achieve this goal by finishing ongoing data analyses as well as by pursuing new measurements. They include: 1) Ongoing and future experimental and phenomenological efforts to constrain the mechanisms for harmonic flow and the nature of the density fluctuations in the initial collision geometry. 2) Future efforts to understand the jet-quenching response to the density fluctuations and to search for medium response to quenched jets. These projects are built upon our established expertise in single particle measurements and jet correlation measurements.
Intellectual merit: These experiments will improve our quantitative understanding of collective behavior and jet-medium interactions, and hence provide invaluable constraints for determining the fundamental properties of high-density nuclear matter under the most extreme conditions.
Broader Impact: Studies of high energy density matter can have a profound impact on our understanding of the strong force in nuclei and the evolution of the early universe, supernova explosions and the properties of neutron stars. The experimental results on jet quenching and medium response at RHIC and LHC have inspired important new developments in super-string theories. Both the PHENIX and ATLAS experiments at these facilities provide excellent training opportunities for graduate, undergraduate and high school students. In addition, the PI is also actively contributing to undergraduate education in nuclear science by teaching in the annual BNL Nuclear Chemistry Summer School.
