A study of medium induced jet modificaiton at the relativistic heavy ion collider via two particle correlations and identified jet spectra

This work has studied the particle composition of jets by determining the ratios p±/π± and K±/π± in Au + Au and d + Au collisions at √sNN = 200 GeV measured by the STAR experiment at RHIC. Jets were found by measuring the angular azimuthal correlation between particles at high transverse momentum. Jets were then identified by their back-to-back correlation. A technique was developed to identify charged particles using their specific ionisation measured in the STAR Time Projection Chamber (TPC). This thesis contains one of the first implementations of using direct photons to tag jets in heavy ion collisions. An attempt was made to extract a trigger sample rich in direct photons from neutral triggers. The hadron ratios were calculated from the jet yields as a function of transverse momentum in each collision system. Although the away side yield is suppressed in central Au + Au, there is no evidence that the relative particle yields are changed. The hadron ratios for the three systems were found to be consistent with simulated p + p events generated using the Pythia Monte Carlo event generator. This reinforces the conclusion that the fragmentation process is unchanged by interactions with the medium