An investigation of pions in nuclear matter and nuclei

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Cahill, Philip Thomas

Contributors dc:contributor

• Ravenhall, D.G.

• pions
• mesons
• Fermi-averaged pion-nuclear matter scattering matrix
• Pauli principle

Statement dc:rights

• 1978 Philip Thomas Cahill

Language dc:language

en

Identifier

312038

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25088