Stopping power and energy deposition in p+A collisions

There has been renewed interest in p+A collisions in the last few years. This has resulted from theoretical speculation that a new state of matter, a Quark Gluon Plasma (QGP), may be the high temperature limit of QCD. Could a QGP be formed for short periods of time in nucleus-nucleus collisions? This question can not be answered until such collisions are actually studied. However, by studying p+A collisions, it may be possible to estimate the conditions that exist in the initial stages of A+A collisions. In particular it has been suggested that by studying the energy loss of the incident proton in p+A collisions an estimate can be made of the maximum baryon and energy densities in central A+A collisions. In this talk the author concentrates on presenting the available data on inclusive leading baryon distributions (pA → pX) as well as data which is relevant to the question of where the energy lost from the leading particle goes. There have been a number of recent experiments which makes such a review relevant at this time. This paper is divided into two sections. He begins by discussing the state of affairs in inclusive leading baryon spectra and then proceeds to a discussion of energy deposition