Author ORCID Identifier
Date Available
4-22-2024
Year of Publication
2024
Degree Name
Doctor of Philosophy (PhD)
Document Type
Doctoral Dissertation
College
Arts and Sciences
Department/School/Program
Physics and Astronomy
First Advisor
Dr. Susan Gardner
Abstract
Studies in quantum chromodynamics (QCD), the fundamental theory of the strong interactions, of low-energy hadronic weak processes utilize an effective Hamiltonian framework. Below the weak-mass scale, an effective Hamiltonian contains a series of Wilson coefficients and four-quark operators that come from the operator product expansion in the Standard Model. The effective hadronic Hamiltonian pertinent to a weak process is then obtained via a renormalization group analysis in QCD from the weak-mass scale to the low-energy scale of O(2 GeV). In this thesis, the construction and phenomenological implications of such an effective Hamiltonian for flavor-conserving, parity-violating quark processes in the Standard Model will be presented. Extensive studies of QCD corrections in flavor-changing meson decays have been conducted starting already in the 1990s. But the status in the flavor-conserving sector is completely different, and such rigorous studies have been lacking. In this work, we establish a robust connection between flavor-conserving and flavor-changing physics and utilize it to find the relevant anomalous dimension matrices for flavor-nonchanging processes through next-to-leading order in QCD. The anomalous dimension matrices represent the renormalization and mixing profile of the operators in the presence of QCD corrections and are an essential ingredient in the renormalization group flow between energy scales. Following the computation of the complete effective low-energy Hamiltonian at GeV scales, we are able to apply it to the study of hadronic parity-violating processes and compute its quantifying parameters, the parity-breaking meson nucleon couplings. The thus computed couplings are shown to be in good agreement with their extracted values from phenomenological analyses of recent, precise measurements of the parity-violating asymmetry in neutron-spin reversal in few-body low-energy nuclear reactions. This has been accomplished for the first time. Finally, we are also able to discuss how this effective Hamiltonian can be applied to studies of weak effects in the hadronic decays of flavor-neutral mesons, such as, η, η′, resulting in P and CP violation. We note how future experiments and lattice QCD studies could sharpen our findings and that our study serves as an essential guide for these future endeavors in arriving at a robust description of hadronic parity violations.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2024.56
Funding Information
U.S. Department of Energy, Office of Nuclear Physics under contract DE-FG02-96ER40989
Recommended Citation
Muralidhara, Girish Lingadahalli, "QCD ANALYSIS OF FLAVOR-NONCHANGING HADRONIC WEAK PROCESSES THROUGH NEXT-TO-LEADING ORDER" (2024). Theses and Dissertations--Physics and Astronomy. 121.
https://uknowledge.uky.edu/physastron_etds/121
