Conor Henderson, Massachusetts Institute of Technology, 7 July 2005.
Advisor: Prof. Gunther M Roland
Transverse momentum ($p_T$) distributions for pions, kaons, protons and antiprotons have been measured near mid-rapidity for Au+Au collisions at $\sqrt{s_{NN}}$~=~62.4~GeV using the PHOBOS detector at the Relativistic Heavy-Ion Collider (RHIC) in Brookhaven National Laboratory.
Particle identification is performed using the PHOBOS Time-of-Flight plastic scintillator walls and specific energy loss in the multi-layer silicon Spectrometer, which is also used for track reconstruction and momentum-determination. The spectra are corrected for all detector-dependent effects, including feed-down from weak decays.
At $p_T \sim 3$~GeV/c, protons are measured to be the dominant species of charged hadrons and scale much faster with respect to collision centrality than mesons.
This behaviour at 62.4~GeV is found to be remarkably similar to that observed in Au+Au collisions at 200~GeV, an interesting observation which should serve as an important constraint on the various mechanisms which have been proposed to describe particle production over this $p_T$ range.
Baryon stopping, the transport of baryon number from intial beam rapidity, is explored through the net proton ($p-\bar{p}$) yields at mid-rapidity. These results fill a large gap between the SPS and higher RHIC energies and as such form an important set of data for comparing to models of baryon transport mechanisms.
Complete thesis