Dissertations, Theses, and Capstone Projects

Date of Degree

9-2018

Document Type

Dissertation

Degree Name

Ph.D.

Program

Physics

Advisor

Brian C. Tiburzi

Committee Members

Stefan Bathe

William Detmold

Jamal Jalilian-Marian

Johannes Kirscher

Subject Categories

Elementary Particles and Fields and String Theory

Keywords

Chiral Perturbation Theory, Nucleons, Hyperons, Landau Levels, LQCD

Abstract

The QCD external field problem allows one to probe the rich behavior of strongly interacting systems under external conditions, including the modification of hadron structure and interactions due to external electromagnetic fields. These dynamics, moreover, are likely relevant to describe the physics in the interiors of magnetars and in non-central heavy-ion collisions, for which large magnetic fields upwards of $10^{19}$ Gauss are conceivable. Additionally motivated by lattice QCD calculations in external fields, we study the behavior of single- and two-baryon (specifically, two-nucleon) systems in large magnetic fields. The dependence of single-baryon energies on magnetic fields is explored using chiral dynamics. Lattice calculations are argued to provide a valuable diagnostic on the chiral expansion for baryons. In particular, we show the unsatisfactory state of predictions for hyperon magnetic polarizabilities. Lattice calculations by the NPLQCD collaboration, furthermore, suggest that the unitary limit of two-nucleon interactions may be attained by tuning an external magnetic field. Toward the investigation of such universality using chiral effective field theory, we study a model system of two heavy fermions interacting with a light, charged scalar boson to address the modification of two-fermion interactions in large magnetic fields.

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