Abstract: The Standard Model of particle physics does not account for dark matter or the origin of neutrino masses. This thesis studies possible extensions of the Standard Model based on flavour symmetries and extended gauge structures. We first consider dark matter within Minimal Flavour Violation and show that flavour symmetries can provide a natural stabilisation mechanism. These models can also give rise to two- or three-component dark matter scenarios with potentially observable signatures. We then study a left–right symmetric model in which Dirac neutrino masses and dark matter arise from the same new particle sector. Neutrino masses are generated at three loops, while an accidental Z2 symmetry stabilises either a scalar or fermionic dark matter candidate. Finally, we examine the effects of two leptoquark models on ultra-high-energy neutrino–nucleon scattering and find that existing LHC constraints exclude most of the parameter space relevant to future neutrino experiments.

Tribunal:

President: Dr. Lluis Garrido Beltran

Secretary: Dr. Lorenzo Calibbi

Vocal: Dr. Luca Di Luzio

Suplents:

Dr. Damir Becirevic

Dr. Eugeni Graugés Pous

Director: Dr. Federico Mescia

Tutor: Dr. Joan Soto Riera