The Development of Computational Tools for Theoretical Predictions in Particle Physics at the Large Hadron Collider
Authors
Advisors
Date
2019-04-27Awarding Institution
University of Cambridge
Author Affiliation
Applied Mathematics and Theoretical Physics
Qualification
Doctor of Philosophy (PhD)
Language
English
Type
Thesis
Metadata
Show full item recordCitation
Cridge, T. H. (2019). The Development of Computational Tools for Theoretical Predictions in Particle Physics at the Large Hadron Collider (Doctoral thesis). https://doi.org/10.17863/CAM.37802
Abstract
The Large Hadron Collider (LHC) experiments are an excellent tool for the improvement of our knowledge of the Standard Model and the examination of Beyond
Standard Model theories. Nonetheless, to maximise the learning-potential of the LHC,
clear and precise theoretical predictions are needed, for both the Standard Model and
its extensions, to allow critical comparison of these models with data. In particular,
given the complexity of the collision environment at the LHC, and the expansive nature
of many parameter spaces of Beyond Standard Model theories, computational programs
to perform theoretical calculations are increasingly required.
The work presented in this thesis fits this role, it is focused on two computational
programs developed with the aim of producing such theoretical predictions for LHC
phenomenology in two key areas. These are the precision Standard Model predictions
of transverse momentum spectra for a wide class of processes at the LHC, and Beyond
Standard Model predictions for the decay widths of as-yet undiscovered particles in the
context of supersymmetry.
Chapter 1 presents a brief chronology and review of the Standard Model. Fol-
lowing this, the work reported in this thesis is split into two parts, focused on the
two main projects undertaken. Chapters 2, 3 and 4 describe the development of the
SoftSusy decay calculator program to determine the partial widths and branching ratios of supersymmetric and Higgs particles in the Minimal Supersymmetric Standard
Model and the Next-to-Minimal Supersymmetric Standard Model. The theoretical and
phenomenological background, methodology, assumptions, and the vast array of decay
modes calculated by the program are described. This is followed by details of the extensive validation of the decay calculator program and a selection of results. Chapter 5
begins the second part of the thesis, providing theoretical background for Chapters 6
and 7, which discuss the newly-developed reSolve program, designed to undertake the
theoretically-demanding calculations associated with transverse momentum resummation for a wide range of LHC processes. Details of the methods, assumptions, validation
and results for channels so far included are all provided, these show excellent agreement
with previous theoretical results and experimental data. Both projects are then summarised in Chapter 8. Further information is provided in the appendices; Appendix A
presents explicitly all formulae incorporated into the SoftSusy decay calculator pro-
gram; whilst Appendix B provides further details on the theoretical underpinning of the
transverse momentum resummation calculations performed by the reSolve program.
Keywords
MSSM, NMSSM, branching ratio, lifetime, Resummation, transverse momentum, precision, differential distributions, diphoton, Drell-Yan, HEP, Particle Physics, LHC, collider phenomenology, Supersymemtry, Standard Model, Beyond Standard Model, QCD
Sponsorship
This work was supported mainly by an STFC PhD Studentship. This work has been partially supported by STFC consolidated grant ST/L000385/1, with further help from the Department of Applied Mathematics and Theoretical Physics and the Cambridge Philosophical Society. In addition a portion of this work was completed whilst supported by a KITP Graduate Fellowship from The Kavli Institute for Theoretical Physics, University of California Santa Barbara via the National Science Foundation under Grant No. NSF PHY-1748958 along with the Gordon and Betty Moore Foundation.
Identifiers
This record's DOI: https://doi.org/10.17863/CAM.37802
Rights
Attribution 4.0 International (CC BY 4.0)
Licence URL: https://creativecommons.org/licenses/by/4.0/
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