# Beyond the Standard Model Physics: Theory and Phenomenology

Lead Research Organisation:
University of Oxford

Department Name: Oxford Physics

### Abstract

The Standard Model of particle physics is now established as a remarkably successful description of physics at the smallest scales probed so far. However, there are many reasons to believe that the Standard Model is incomplete. The nature of dark matter and dark energy remains mysterious, even as their existence has overwhelming evidence from cosmology and astrophysics. The origin of the electroweak scale and patterns of couplings in the Standard Model also call for an explanation. Remarkably, solutions to these shortcomings are often within our experimental reach. The research in this thesis will be in theoretical particle physics, focusing on physics beyond the Standard Model.

The central question for this thesis is: Where is new physics, and how will we find it? This is a necessarily wide-ranging enterprise, with inputs from new quantum field theory methods and string theory, from new model building techniques as well as new experimental results. A large number of experiments can be brought to bear on this question - direct and indirect detection for dark matter, collider experiments, cosmological and astrophysical measurements, small scale experiments for axion detection, gravitational wave measurements to name a few. A part of the research in this thesis will engage with experimental signatures of new physics, both in existing experiments as well as with an aim to design new ways to look for new physics.

Another aspect of research for this thesis will interface with developments in formal areas of theoretical particle physics. A key new development in theoretical physics is the idea of the Swampland. The theory of quantum gravity is thought to be much more restrictive than consistent quantum field theories. In the context of string theory, it is thought that there is only one unique consistent theory. However, there are a large number of potential solutions of this theory, making it hard to derive predictions. The Swampland program posits that the number of solutions of string theory themselves are limited. Otherwise consistent quantum field theories do not arise in theories of quantum gravity. Delineating the boundary of the Swampland is an active field of research, and in the absence of a complete understanding of string theory relies on extrapolating our experience with it. Often, the predictions derived from Swampland conditions are testable, making it an exciting venue for deriving experimental signatures from quantum gravity.

The research in this thesis will reside in this exciting hub of connections between formal theory, particle phenomenology model building and cosmology.

Another aspect of research for this thesis will interface with developments in formal areas of theoretical particle physics. A key new development in theoretical physics is the idea of the Swampland. The theory of quantum gravity is thought to be much more restrictive than consistent quantum field theories. In the context of string theory, it is thought that there is only one unique consistent theory. However, there are a large number of potential solutions of this theory, making it hard to derive predictions. The Swampland program posits that the number of solutions of string theory themselves are limited. Otherwise consistent quantum field theories do not arise in theories of quantum gravity. Delineating the boundary of the Swampland is an active field of research, and in the absence of a complete understanding of string theory relies on extrapolating our experience with it. Often, the predictions derived from Swampland conditions are testable, making it an exciting venue for deriving experimental signatures from quantum gravity.

The research in this thesis will reside in this exciting hub of connections between formal theory, particle phenomenology model building and cosmology.

The central question for this thesis is: Where is new physics, and how will we find it? This is a necessarily wide-ranging enterprise, with inputs from new quantum field theory methods and string theory, from new model building techniques as well as new experimental results. A large number of experiments can be brought to bear on this question - direct and indirect detection for dark matter, collider experiments, cosmological and astrophysical measurements, small scale experiments for axion detection, gravitational wave measurements to name a few. A part of the research in this thesis will engage with experimental signatures of new physics, both in existing experiments as well as with an aim to design new ways to look for new physics.

Another aspect of research for this thesis will interface with developments in formal areas of theoretical particle physics. A key new development in theoretical physics is the idea of the Swampland. The theory of quantum gravity is thought to be much more restrictive than consistent quantum field theories. In the context of string theory, it is thought that there is only one unique consistent theory. However, there are a large number of potential solutions of this theory, making it hard to derive predictions. The Swampland program posits that the number of solutions of string theory themselves are limited. Otherwise consistent quantum field theories do not arise in theories of quantum gravity. Delineating the boundary of the Swampland is an active field of research, and in the absence of a complete understanding of string theory relies on extrapolating our experience with it. Often, the predictions derived from Swampland conditions are testable, making it an exciting venue for deriving experimental signatures from quantum gravity.

The research in this thesis will reside in this exciting hub of connections between formal theory, particle phenomenology model building and cosmology.

Another aspect of research for this thesis will interface with developments in formal areas of theoretical particle physics. A key new development in theoretical physics is the idea of the Swampland. The theory of quantum gravity is thought to be much more restrictive than consistent quantum field theories. In the context of string theory, it is thought that there is only one unique consistent theory. However, there are a large number of potential solutions of this theory, making it hard to derive predictions. The Swampland program posits that the number of solutions of string theory themselves are limited. Otherwise consistent quantum field theories do not arise in theories of quantum gravity. Delineating the boundary of the Swampland is an active field of research, and in the absence of a complete understanding of string theory relies on extrapolating our experience with it. Often, the predictions derived from Swampland conditions are testable, making it an exciting venue for deriving experimental signatures from quantum gravity.

The research in this thesis will reside in this exciting hub of connections between formal theory, particle phenomenology model building and cosmology.

### Studentship Projects

Project Reference | Relationship | Related To | Start | End | Student Name |
---|---|---|---|---|---|

ST/T506333/1 | 30/09/2019 | 29/09/2023 | |||

2397217 | Studentship | ST/T506333/1 | 30/09/2020 | 31/03/2024 | Arthur Carel Platschorre |