Topics in Theoretical and Experimental Relativistic Heavy-Ion Physics

by Jeremy Alford

Institution: Kent State University
Department: College of Arts and Sciences / Department of Physics
Degree: PhD
Year: 2015
Keywords: Nuclear Physics
Record ID: 2062638
Full text PDF: http://rave.ohiolink.edu/etdc/view?acc_num=kent1429502362


Much can be learned about the quark-gluon plasma created in relativistic heavy-ion collisions by studying the particles produced. In addition to particles being created from the energy released, these collisions are expected to produce very strong magnetic fields. Although these fields only exist for a tiny fraction of a second, their existence may influence particle production. I will present a theoretical analysis of heavy quarkonia subjected to a very strong magnetic field and an experimental search for hypertriton, an exotic, unstable isotope of hydrogen.For the theoretical part of my dissertation, I model the interaction of a heavy quark-antiquark pair using a non-relativistic Hamiltonian. The Schrodinger equation is solved numerically using the model Hamiltonian including spin-spin, spin-orbit, and tensor interactions. I will present the energy eigenstates as a function of the external magnetic field for all 1s and 1p bottomonium and charmonium states. A very strong magnetic field is expected to modify the masses of quarkonia enough to be measured in modern collider experiments and may help to explain the suppression of J/¿ mesons observed in relativistic heavy-ion collisions. The changes in mass are due to the interaction with the magnetic field as well as the mixing between spin states.For the experimental part of my dissertation, I look for evidence of a hypertriton decaying into a deuteron, proton and pion. Hypertritons are created in relativistic heavy-ion collisions at RHIC and the decay products are observed using the STAR detectors. The relativistic invariant mass of the hypertriton candidates is calculated using energy-momentum conservation of the decay products. The resulting invariant mass spectrum is then examined for an abundance of candidates near the known hypertriton mass. Although the combinatorial background for a three-body decay is much larger than for a two-body decay, the large amount of data acquired in recent years combined with the higher branching ratio for the three-body decay makes it reasonable to expect that a good signal can be extracted