Transverse Energy Distributions in Ultra Relativistic Light Ion Collisions and Impact Parameter Correlations in Nucleon-Nucleon Interactions.

Ultra-relativistic (sqrt{s } gg m_ {p}) p-nucleus and nucleus-nucleus collisions provide an interesting setting for studying the interaction of hadronic matter. The large energy densities involved in these processes offer the hope of observing new phenomena, such as the deconfinement of quarks and gluons from the usual hadronic and mesonic states. In searching for such new physics in the collisions of large nuclei, it is important to understand particle production in light nuclei first, since in these systems, complicating factors such as reinteraction of collision products with other nucleons are small. Thus collisions of light nuclei can establish a baseline from which to understand the more complex interactions of larger nuclei. This thesis contains three parts. In the first, the results of pp, alphaalpha, palpha, and deuteron-deuteron collisions at sqrt{s} = 31 GeV in the nucleon-nucleon center of mass are studied. These data were recorded in 1983 with the Axial Field Spectrometer, during a special run at the CERN ISR. The transverse energy (E_{t}) distributions in these four reactions, as measured with a uranium/copper/scintillator sampling calorimeter, are presented. The Wounded Nucleon Model, as extended to treat distributions of observables, is compared with the data. This model postulates that the number of participant, or struck, nucleons determines event parameters such as multiplicity and E_ {t}. This approach is found to fit the cross sections over many decades, although it fails for the high E_{t} portion of the alphaalpha data. A Multiple Scattering Model, used by others in attempts to understand interactions of heavy nuclei, assumes that the number of nucleon-nucleon collisions is the relevant parameter. To obtain even poor fits to the E_{t} data with this model requires extremely unphysical assumptions. In the second part of the thesis, a model is presented for estimating the multiplicity accompanying the production of jets, W and Z bosons, and other processes, using impact parameter correlations. We show how the background multiplicity in such events can possibly be used to learn about the spatial distribution of the constituents involved in the interaction. Detailed comparison of model predictions are made with recent data on prompt positron production. The variation of < p_ {t}> and the charged particle density vs. pseudorapidity are examined to very large values of E_{t} in sqrt{s} = 31 GeV pp collisions, made possible by the use of a large solid angle calorimeter. Measurements of < p_{t}> and the charge particle density are also presented, extending previous measurements using only charged E _{t}. This provides new data with which to test models of low p_{t} particle production. Possible isotropy of events at high E_{t} is examined as a signal of stopped protons.