Dark Matter Searches via B-Physics and Neutrino Physics

Abstract

This thesis tackles the problem of the nature of Dark Matter using two different approaches: B-physics and neutrino-physics. A model independent strategy is implemented to study B meson decays for evidence of WIMPs in FCNC processes. The Wilson coefficients CDM responsible for transitions with dark matter scalars are constrained using experimental bounds on different B meson decay processes B ! M ; these bounds are also used to determine the phase space for the mass of the dark matter candidate. Our results show that the decay processes with vector meson final states prove more promising for studying due to the availability of a larger phase space. Additionally, the applied constraints prefer smaller CDM values. Also, the Majorana nature of neutrinos is probed using BSM extensions of the Krauss- Nasri-Trodden model to study same-sign dilepton signatures eð€€€eð€€€ ! `ð€€€ `ð€€€ + Emiss for the feasibility of detecting dark matter at current and future colliders. Analysis performed on a selection of benchmarks obeying relic density, lepton flavour violation and muon anomalous magnetic moment shows that a mass hierarchy is favoured wherein MS2 < MS1 ; the constraints permit a larger number of benchmarks with heavier dark matter candidates (MN1 ); in order to fulfil relic density and annihilation cross-section bounds, the gi Yukawa couplings responsible for interactions of N1, must be larger than the f couplings. A single benchmark is chosen for more detailed study; a scan of the interaction cross sections for a range of ECM values showed the minimum required energy for producing all channels is 400 GeV. The cuts applied to various kinematic variables, for improving the visibility of the events in excess of the SM events, are also discussed. The cuts and constraints help narrow the favoured range for the mass of the dark matter Majorana neutrino candidate to MN1 . 100 . 150 GeV. Additional methods for studying signal detectability and improving the signal-to-noise ratio are briefly discussed.