Adapting the Multilepton Final States to Complex Models

Abstract

The standard model of particle physics has several shortcomings, such as the origin of neutrino masses, dark matter candidates and baryon asymmetry. Several searches for beyond standard model (BSM) phenomena have been conducted. One paper probes new phenomena in multilepton final states and searches for new particles arising in type-III seesaw, singlet and doublet models of vector-like leptons and scalar leptoquark models. However, this paper treats each of these models as independent. Recent theoretical developments propose models with vector-like leptons as well as leptoquarks or models of seesaw fermions with additional scalars. Such models present unique challenges to existing searches due to the higher number of theoretical parameters, as well as complex decay topologies. In this thesis, we will study such models of mixed particles and how a multilepton search can be designed to have high sensitivity to such models. We aim to build a robust analysis strategy that targets the multiple theoretical parameters in a systematic way.