The nuclear physics program at Creighton University investigates the behavior of nuclear matter under extreme conditions. We make use of the wide variety of heavy ion and proton beams available at the Relativistic Heavy Ion Collider (RHIC), using the STAR (Solenoidal Tracker At RHIC) detector, and at the Large Hadron Collider (LHC), using the ALICE (A Large Ion Collider Experiment) detector. The scientific focus of our group is the production of particles in ultra-peripheral collisions, where the colliding nuclei do not physically overlap. In these 'near-miss' collisions, we probe the effects of intense long-range electromagnetic interactions. The electromagnetic field of a highly relativistic charged particle is viewed as a flux of virtual photons with a continuous energy spectrum. The objective of our research is to create an experimental understanding of how photons and nuclei interact. Interactions involving heavy ions are particularly useful for this type of research because the flux of virtual photons increases as the charge on the ions increases. At speeds near the speed of light, the density of the electromagnetic field also increases due to a significant Lorentz contraction. This dense flux of virtual photons can interact with nuclei or other virtual photons to produce new particles, advancing the understanding of fundamental interactions involving both the electromagnetic and strong nuclear forces. Ultra-peripheral collisions of heavy ions provide an opportunity to learn about fundamental aspects of nuclei, such as the density of gluons inside the nucleus. This information in turn provides a better understanding of the initial state of nuclei prior to head-on collisions and gives insight into the thousands of nearly simultaneous individual interactions that make up the complex head-on collision of two heavy nuclei. The LHC is the most energetic photon source built to date, allowing a wide range of particles to be studied. RHIC, while lower in photon energy, provides high statistics datasets and allows a comparative study of a variety of nuclei at several different energies. Because of the complementary nature of the colliders, it is advantageous to be involved in both experiments. Our group is also involved in the continued development of Starlight, a widely-used computer code that models the ultra-peripheral collisions of relativistic heavy ions and produces simulated events. Finally, our group provides support for the successful operation, maintenance and development of the hardware controls systems for both the STAR experiment and the ALICE Electromagnetic Calorimeter. The participation of undergraduate and graduate students, and their training for successful scientific careers, is an integral aspect of this program.
|Effective start/end date||7/1/20 → 6/30/23|
- Nuclear Physics: $5,191,900.00