No description available.

No description available.

No description available.

Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The aim of this work was to study the 208Pb(p,2p)207Tl quasi-free knockout process. The experimental data were measured at the National Accelerator Centre using incident polarised protons of 200 MeV. The two scattered particles, from the knockout reaction, were detected in coincidence and their energies were determined using a magnetic spectrometer and a solid state detector telescope. Cross section and analysing power energy distributions were extracted from the experimental measurements and these were compared with theoretical values for the Distorted Wave Impulse Approximation. The theoretical cross-section calculations predict the experimental cross-section distribution well for all combinations of distorting potentials and bound states that were investigated, both with regard to shape, as well as absolute magnitude. However the theoretical analysing power distributions did not agree with the experimental quantities. Therefore it is not clear whether the analysing power is a useful tool to extract information on the specifics of the quasi-free reaction mechanism. The spectroscopic factors were found to be consistent with the results obtained in previous studies, thereby inspiring confidence that the problem with the analysing power distribution is not ascribable to a possible deficiency in the experimental techniques exploited in this work. / AFRIKAANSE OPSOMMING: Die doel van die studie was om die kwasi vrye 208pb(p,2p )207TI verstrooingsproses te ondersoek. Die eksperimentele data is ingewin by die Nasionale Versnellingsentrum deur gebruik te maak van 'n 200 MeV gepolariseerde proton bundel. Die twee verstrooide deeltjies is in koïnsidens gemeet. Vir die metings is 'n magnetiese spektrometer en 'n vastetoestand detektorteleskoop gebruik. Die kansvlak- en analiseervermoë-energieverdelings is uit die eksperimentele data verkry en is vergelyk met die berekenings van die Vervormde Golf Impuls Benadering. Die teoretiese kansvlak berekening het die eksperimetele data goed voorspel, vir die verskillende parametrisering van potensiaal en gebonde toestande. Die berekeninge het goed ooreengestem met betrekking tot beide vorm en absolute grootheid. Die berekende analiseervermoë het egter nie goed met die eksperimentele data ooreengestem nie. Dit is dus nie duidelik of die analiseervermoë 'n handige instrument is om inligting oor die betrokke kwasi-vrye reaksie meganisme te bekom nie. Die spektroskopiese faktore was in ooreenstemming met resultate wat in vorige studies verkry is. Dit versterk vertroue dat die probleem met die analiseervermoë nie toegeskryf kan word aan die eksperimentele tegniek wat gebruik is nie.

Measurements of the differential cross-section for elastic scattering of positive and negative kaons off of a proton target are given in this dissertation. The beam momenta were 100 GeV/c and 200 GeV/c. The range of t, the four momentum transfer squared, measured was 0.4 < -t < 3.0. The experiment was performed at Fermilab. The data is consistent with previous experiments. Because of the much greater statistical accuracy of this experiment, it is now clear that the apparent equality of the pion and kaon cross-sections at larger t was due to poor statistical accuracy. The experimental results are not predicted by any theory. Furthermore, the difference between the pion and kaon differential cross-sections is not explained by geometrical scaling, as it was in the past.

Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.

A Monte-Carlo simulation program of the response of the Endcap Electromagnetic Calorimeter (EEMC) and Shower Maximum Detector (SMD) was developed to determine the ability, of the detectors, to provide y/n° discrimination and calculate the effects crosstalk between readout channels from multianode photomultiplier tubes (MAPMT). The importance of this discrimination process is to allow a better measure of the direct-photon asymmetries, which are then used to calculate the gluon contribution to the proton spin structure. These measurements arise from polarized-proton collisions provided by the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory and are detected using the Solenoidal Tracker at RHIC (STAR), which includes the EEMC and SMD. In order to obtain accurate asymmetry measurements, the photons resulting from 7c° decay must be identified through pion-mass reconstruction to avoid confusing them as direct photons. This Monte-Carlo simulation and reconstruction algorithm successfully identified 60% of the pions from single-pion events and 40% of the pions from two-pion events. The effects of MAPMT crosstalk, as determined by the Monte Carlo, were less than 2% on n° identification, and therefore were determined to be insignificant. / Department of Physics and Astronomy

M.S.

M.S.

Proton Compton scattering has been studied from 220 to 330 MeV at 90 degree center of mass scattering angle with the polarized photon beam at LEGS. Compton scattering is an important probe of the nucleon structure and its excited states. Polarization degrees of freedom reveal more information than unpolarized observables. This experiment measured, for the first time, the polarized cross sections of proton Compton scattering up to the Δ resonance. The parallel and perpendicular cross sections were measured at the same time. All the photons were tagged so that the energy dependent systematic errors are small. The measured unpolarized cross section is above the lower bound from unitary at all energies. The cross section asymmetry is obtained as a function of energy for the first time. The unpolarized cross section is compared with previous data and with calculations from the fixed-t dispersion model, the isobar model and the finite energy dispersion model. Although all these calculations agree fairly well with unpolarized cross section data, the photon asymmetry data show that the isobar model contains serious defects. The ratio of polarized cross sections, dσ_⫫/dσ_⟂, is compared with a model independent result. The results from the present experiment can be used in the calculation of the E2/M1 ratio in the N — Δ transition, which is an important signature of the tensor interaction between quarks. / Ph. D.