Please use this identifier to cite or link to this item: http://doi.org/10.25358/openscience-5216
Authors: Madge Pimentel, Eric
Title: Phenomenology of New Physics Models at Colliders and in Gravitational Waves
Online publication date: 23-Oct-2020
Year of first publication: 2020
Language: english
Abstract: The existence of physics beyond the Standard Model of particle physics is very well motivated. This dissertation studies the phenomenology of models that accommodate such new physics. It mainly covers two aspects: collider phenomenology and gravitational waves. We first present a search for Higgs-portal dark matter at the LHC and its prospective high-luminosity and high-energy upgrades, entertaining the vector-boson fusion channel. We derive the limits on the portal coupling as a function of the dark matter mass, in particular also for masses close to the transition between the on- and off-shell Higgs regime. Subsequently, a study of the h → Zγ decay in top-pair associated production is considered. We evaluate the observational prospects at future proton colliders and derive the corresponding indirect constraints that can be put on the new physics’ contribution to the decay rate. Our exploration of collider probes of physics beyond the Standard Model is then concluded with a comprehensive analysis of the phenomenology of a model in which lepton number is gauged. The model automatically provides a candidate for particle dark matter. We investigate the parameter space in which the measured relic abundance is reproduced, impose constraints from direct and indirect dark matter searches, and assess the limits from collider experiments. We then move on to study the gravitational wave phenomenology of new physics, focusing on stochastic gravitational wave backgrounds generated in cosmological first-order phase transitions. After an introduction to the topic, we return to the gauged-lepton-number-model and investigate the lepton number breaking phase transition. We identify the parameter regions in which the transition is of first order and which are consistent with the collider and dark matter constraints. We then calculate the respective gravitational wave spectrum and evaluate its detectability at LISA and other future gravitational wave observatories. Finally, we consider phase transitions occurring in decoupled dark sectors, particularly focusing on sub-MeV hidden sectors. We investigate the interplay between cosmological constraints on the number of relativistic degrees of freedom and the detectability of the gravitational wave background generated by a phase transition in such a sector.
DDC: 530 Physik
530 Physics
Institution: Johannes Gutenberg-Universität Mainz
Department: FB 08 Physik, Mathematik u. Informatik
Place: Mainz
ROR: https://ror.org/023b0x485
DOI: http://doi.org/10.25358/openscience-5216
URN: urn:nbn:de:hebis:77-openscience-2a296ee6-f771-4ace-b7e6-d3d9e44748506
Version: Original work
Publication type: Dissertation
License: In Copyright
Information on rights of use: https://rightsstatements.org/vocab/InC/1.0/
Extent: viii, 177 Seiten
Appears in collections:JGU-Publikationen

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