Neutral Pion and Direct Photon Production in the SPS Energy Regime

This thesis presents analyses of experimental data from two heavy-ion experiments:  the PHENIX experiment has obtained data of Cu+Cu collisions at center-of-mass energy of 22.4 GeV, close to the top energy of the SPS accelerator for heavy ions. WA98 has recorded data sets from p+Pb and p+C collisions at √sNN = 17.3 GeV. Two possible signatures of a QGP are the focus of these analyses: the search for experimental evidence of jet quenching and the search for a thermal direct photon signal.