It is a well-established fact that protons and neutrons are made up of smaller constituents called quarks and gluons. In collisions using two beams of heavy nuclei, a new state of matter is formed from these constituents, called the quark-gluon plasma (QGP). This project will answer fundamental questions about the QGP, such as the space-time dynamics of the matter and its transport properties. The project will be carried out by studying the collective flow of fluctuations and particle interactions with the QGP. Studies of high energy density matter can have a profound impact on our understanding of the theory of Quantum Chromodynamics (QCD), which governs the behavior of nuclei and the evolution of the early universe, supernova explosions and the properties of neutron stars. The research will be carried out at the Large Hadron Collider in Europe, using the ATLAS detector, and at the Relativistic Heavy Ion Collider of Brookhaven National Laboratory, using the STAR detector. Both the ATLAS and STAR experiments provide excellent training opportunities for graduate, undergraduate and high school students.
The proposed measurements include: 1. Comprehensive model studies of particle correlations in transverse and longitudinal directions as compared with measurements to constrain the dynamics and properties of the matter in A+A collisions. This effort requires inventing new analysis methods, developing event-shape triggers to take advantage of the upcoming high-luminosity Pb+Pb run, as well as carrying out similar analyses at lower collision energy at RHIC. 2. Detailed investigations of long-range ridge correlations in small systems such as pp and p+Pb collisions, which require development of high-multiplicity triggers, improving the multi-particle correlation method, as well as studying the particle mass dependence of the ridge correlation. 3. Future efforts to understand the jet-quenching response to the initial density fluctuations and to search for medium response to quenched jets. The proposed efforts are built upon the group's established expertise in various correlation measurements.
