Various Phenomenological Aspects of the R-parity Violating MSSM

Abstract

The Standard Model (SM) faces both theoretical and experimental challenges that indicate the existence of physics beyond its current framework. Among the proposed extensions, supersymmetry (SUSY) emerges as a promising concept. The simplest extension of the SM, which incorporates SUSY, is the Minimal Supersymmetric Standard Model (MSSM). It provides a potential candidate for dark matter and offers solutions to the hierarchy problem. As part of the definition of the MSSM, imposing a discrete R-parity (𝑅_𝑝), to prevent proton decay, forbids every term in the Lagrangian that violates baryon or lepton number. However, imposing this symmetry is not necessary. Models that violate R-parity (RPV) exhibit a rich and diverse phenomenology different from the 𝑅_𝑝-conserving MSSM and provide a more original mechanism for neutrino mass production. <br/> This thesis addresses the phenomenology of the RPV-MSSM by identifying different characteristic regions within the RPV-MSSM landscape and exploring their signatures. Depending on the choice of RPV couplings, the framework may exhibit potential gaps in the coverage. We try to provide studies, which potentially close these gaps and try to give an overview of the vast RPV-MSSM landscape. <br/> By analyzing the structures of the neutrino mass matrix, we identify minimal models for understanding neutrino masses in the 𝐵₃-conserving RPV-MSSM. These models provide valuable insights into understanding neutrino masses, in the general context of RPV scenarios that have not been analyzed. <br/> We use several collider experiments to investigate how different types of signals can be revealed as a result of the choice and strength of RPV couplings as well as the mass of SUSY particles. We present a systematic analysis of the RPV-MSSM and its collider signatures to find a minimal number of experimental searches for comprehensive LHC coverage. The lightest neutralino with a mass of 𝒪(GeV) and small couplings is unconstrained in the RPV-MSSM. We present three approaches for both constraining the coupling parameters and exploring the sensitivity regions of future experiments. We consider neutralino production in meson decays via 𝐿𝑄<span style="text-decoration:overline">𝐷</span> operators, followed by loop-induced decays into a photon and a neutrino in <TT>FASER</TT>. We re-interpret experimental results, derived for heavy neutral leptons (HNL), to constrain the RPV couplings. And we study a novel proton decay involving a bino-like neutralino and the resulting decay signature. <br/> Our approach emphasizes the potential of future experiments, including those not specifically designed for SUSY searches, to effectively probe the RPV landscape.