Meson Masses in the Unquenched Quark Model

KENNELLY, JACK

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Meson Masses in the Unquenched Quark Model / JACK KENNELLY

Swansea University Author: JACK KENNELLY

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Abstract

A novel approach to calculating coupled-channel eﬀects for bottomonium in the 3P0 framework using realistic wavefunctions is introduced in which the physical state is expanded in a basis set of harmonic oscillators. Other techniques of solving the unquenched system are also presented including pertu...

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Published:	Swansea 2022
Institution:	Swansea University
Degree level:	Master of Research
Degree name:	MSc by Research
Supervisor:	Burns, Timothy
URI:	https://cronfa.swan.ac.uk/Record/cronfa59927
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first_indexed	2022-04-29T14:31:59Z
last_indexed	2022-04-30T03:30:56Z
id	cronfa59927
recordtype	RisThesis
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spelling	2022-04-29T15:43:56.0866802 v2 59927 2022-04-29 Meson Masses in the Unquenched Quark Model 8c0fc7e3b6ce4f0ab2c520ebf97a1d41 JACK KENNELLY JACK KENNELLY true false 2022-04-29 A novel approach to calculating coupled-channel eﬀects for bottomonium in the 3P0 framework using realistic wavefunctions is introduced in which the physical state is expanded in a basis set of harmonic oscillators. Other techniques of solving the unquenched system are also presented including perturbative, simple harmonic oscillator and unique valence approximations. The resulting (spin-averaged) mass shifts are calculated for an nS → 1S +1S transition and compared across the separate methods. It is determined that the largest eﬀect on the mass shift across the various approaches is the accu-rate treatment of the wavefunction, which causes signiﬁcant deviations from the simple harmonic oscillator approximation near threshold. It is also found that the inclusion of mixing between valence states due to meson loops has no eﬀect at ground state energies but induces small diﬀerences at higher lying states. While conclusions are drawn about the relative eﬀect each of the methods presented have on determining the mass shift due to unquench-ing, further research is suggested for other transitions to be assured in such conclusions. E-Thesis Swansea Meson, Quark, Unquenched, Harmonic Oscillator 27 4 2022 2022-04-27 COLLEGE NANME COLLEGE CODE Swansea University Burns, Timothy Master of Research MSc by Research 2022-04-29T15:43:56.0866802 2022-04-29T15:29:54.4782432 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Physics JACK KENNELLY 1 59927__23939__bd3749539a5a446fb08219654eb6f0da.pdf Kennelly_Jack_MSc_Research_Thesis_Final_Cronfa.pdf 2022-04-29T15:34:57.1587444 Output 502489 application/pdf E-Thesis – open access true Copyright: The author, Jack Kennelly, 2022. true eng
title	Meson Masses in the Unquenched Quark Model
spellingShingle	Meson Masses in the Unquenched Quark Model JACK KENNELLY
title_short	Meson Masses in the Unquenched Quark Model
title_full	Meson Masses in the Unquenched Quark Model
title_fullStr	Meson Masses in the Unquenched Quark Model
title_full_unstemmed	Meson Masses in the Unquenched Quark Model
title_sort	Meson Masses in the Unquenched Quark Model
author_id_str_mv	8c0fc7e3b6ce4f0ab2c520ebf97a1d41
author_id_fullname_str_mv	8c0fc7e3b6ce4f0ab2c520ebf97a1d41_***_JACK KENNELLY
author	JACK KENNELLY
author2	JACK KENNELLY
format	E-Thesis
publishDate	2022
institution	Swansea University
college_str	Faculty of Science and Engineering
hierarchytype
hierarchy_top_id	facultyofscienceandengineering
hierarchy_top_title	Faculty of Science and Engineering
hierarchy_parent_id	facultyofscienceandengineering
hierarchy_parent_title	Faculty of Science and Engineering
department_str	School of Biosciences, Geography and Physics - Physics{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Physics
document_store_str	1
active_str	0
description	A novel approach to calculating coupled-channel eﬀects for bottomonium in the 3P0 framework using realistic wavefunctions is introduced in which the physical state is expanded in a basis set of harmonic oscillators. Other techniques of solving the unquenched system are also presented including perturbative, simple harmonic oscillator and unique valence approximations. The resulting (spin-averaged) mass shifts are calculated for an nS → 1S +1S transition and compared across the separate methods. It is determined that the largest eﬀect on the mass shift across the various approaches is the accu-rate treatment of the wavefunction, which causes signiﬁcant deviations from the simple harmonic oscillator approximation near threshold. It is also found that the inclusion of mixing between valence states due to meson loops has no eﬀect at ground state energies but induces small diﬀerences at higher lying states. While conclusions are drawn about the relative eﬀect each of the methods presented have on determining the mass shift due to unquench-ing, further research is suggested for other transitions to be assured in such conclusions.
published_date	2022-04-27T04:17:36Z
_version_	1763754174265163776
score	11.013371

Meson Masses in the Unquenched Quark Model / JACK KENNELLY

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