2026-09-23T05:39:32Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/25088 2023-07-10 col_2142_8859 col_2142_5131 com_2142_8858 com_2142_234 com_2142_5130

Ravenhall, D.G. Cahill, Philip Thomas 2011-05-31T18:20:56Z 2011-05-31T18:20:56Z 10000-01-01 1978 The Fermi-averaged pion-nuclear matter scattering matrix in the region of the N*(1232) resonance is calculated using two models, one incorporating a single channel (1=1) potential separable in the pion-nucleon relative coordinate and a realistic nucleon pseudopotential to investigate the effects of the Pauli Principle and nucleon recoil and binding, and the other fixing the positions of the nucleons to investigate the effects of two-nucleon scattering and correlations. The main results are that nucleon recoil and the Pauli Principle can combine in a manner which significantly enhances the averaged scattering matrix element by allowing the trajectory of the pole in that matrix element to intersect the real axis, an effect extended to higher incident pion momentum by the binding due to the pseudopotential; that two-nucleon correlations in the Fermi sea ground state introduce only a small effect (approximately ten percent) to the scattering; and that two-nucleon encounters drastically change the size and shape of the resulting pion-nuclear matter optical potential, invalidating the application of a lowest-order optical potential in this energy regime. An estimate utilizing the exact model wave functions is made of the matrix elements describing pion-two-nucleon scattering and pion absorption and re-emission on two nucleons, which indicates that these two processes are approximately of equal importance. Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-05-31T18:20:56Z No. of bitstreams: 1 1978_cahill.pdf: 4660573 bytes, checksum: c9544e7d086566572348b041ee74c35c (MD5) Made available in DSpace on 2011-05-31T18:20:56Z (GMT). No. of bitstreams: 1 1978_cahill.pdf: 4660573 bytes, checksum: c9544e7d086566572348b041ee74c35c (MD5) Previous issue date: 1978 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-05-31T18:20:56Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:15:17-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis Thesis U of I Only 312038 http://hdl.handle.net/2142/25088 en 1978 Philip Thomas Cahill pions mesons Fermi-averaged pion-nuclear matter scattering matrix Pauli principle An investigation of pions in nuclear matter and nuclei Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.