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Elastic scattering data was successfully taken using the new "Clamshell" spectrometer. Angular distributions of elastic differential cross sections were obtained at 50 MeV and 65 MeV using positive and negative pions scattered from ⁵⁶Ni, ⁶⁰Ni, and ⁶⁴Ni. The data were compared to predictions made using the MSU optical potential, The π⁺ data agreed fairly well with the predictions at both 50 MeV and 65 MeV while the corresponding π⁻ data significantly disagreed with the predictions. The absorption parameters in the MSU potential were varied in an attempt to fit the data. A suitable fit was achieved for both π⁺ and π⁻ data at 50 MeV and 65 MeV. The real part of the p-wave absorption parameter was well determined but showed two distinct values for π⁺ and π⁻ indicating that there is a separate potential for π⁺ and π⁻ or that the absorption part of the potential is inadequately formulated. / Ph. D.

Graduation date: 1997

Thesis (M.S.)--Auburn University, 2008. / Abstract. Includes bibliographical references (p. 29-30).

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--University of California, Berkeley, 1962. / "UC-34 Physics" -t.p. "TID-4500 (17th Ed.)" -t.p. Includes bibliographical references (p. 61-62).

Orientador: Adriano Antônio Natale / Banca: José Ricardo Marinelli / Banca: Fernando Mori / Resumo: Neste trabalho, investigamos a viabilidade do mecanismo de pólo do píon ('gama"gama"seta"'pi'POT.0"seta"niu"niu'BARRA') como mecanismo alternativo para o resfriamento do núcleo estelar de estrelas de alta massa durante o processo de colapso gravitacional. Em especial, concentramos nossa atenção no vínculo para a luminosidade de neutrinos emitidos pela supernova SN1987A. Mostramos que ao incorporar os efeitos do meio nuclear denso no propagador piônico através da eoria de Migdal para sistemas fermiônicos finitos, o mecanismo de pólo do píon é suprimido e que por causa diss não conseguimos obter nenhum vínculo significativo para o decaimento do píon em neutrinos. / Abstracts: In this work, we investigate the viability of the pion pole mechanism ('gama"gama"seta"'pi'POT.0"seta"niu"niu'BARRA') as an alternative mechanism for the cooling of stellar nucleus of massive stars during the gravitational collapse. In particular we concentrate our attention on a possible constrain on the neutrino's luminosity from the supernova SN1987A. We show that incorporating the effects of the dense nuclear medium througt the Migdal's theory for finite fermionic systems in the pion propagator, the pion pole mechanism is supressed and we cannot obtain any meaningful constrain for the pion decay into neutrinos. / Mestre

No description available.