UC Davis

The RHIC Beam Energy Scan Phase-I (BES-I) program began a systematic study of the QCD phase diagram with the intent to identify the location of the critical point and prove the existence of a first order phase transition at high baryon chemical potential. While it made progress toward those goals, large statistical uncertainties and an energy range restricted by accelerator design limited the possible conclusions. The second phase of the BES program (BES-II), in conjunction with the STAR Fixed-Target (FXT) program, will allow for more precise measurements and cover a larger energy range.

This dissertation will present the results from the lowest energy of the STAR Fixed-Target program, $\sqrt{s_{NN}}=3.0$ GeV. Invariant yields of pions ($\pi^{\pm}$), kaons ($K^{\pm}$), and protons ($p$) are measured in a broad phase-space and, along with the rapidity density distributions of these charged hadrons, will be used to help unravel the relative importance of the different particle production mechanisms. Trends across centrality are investigated, along with trends in collisions energy. These measurements provide an in-depth study of the various production mechanisms for light hadrons and probe unique properties of the high baryon density medium produced in these low energy collisions.