TEV SCALE SUPERSYMMETRIC EXTENSIONS OF THE STANDARD MODEL AT THE LARGE HADRON COLLIDER

Abstract

We study the phenomenological and cosmological implications of B 􀀀L extension of the SM in both supersymmetric (BLSSM) and non-supersymmetric (BLSM) scenarios. We show that generating non-vanishing neutrino masses through TeV inverse seesaw mechanism leads to a cuto scale of SM Higgs potential stability of order 105 GeV. However, in the BLSM we nd that the mixing between the SM-like Higgs and the B 􀀀L Higgs plays a crucial role in alleviating the vacuum stability problem. We also provide the constraints of stabilizing the Higgs potential in the supersymmetric B 􀀀 L model. In addition the predicted sneutrino-antisneutrino oscillation phenomena is explored in the BLSSM, where a type I seesaw mechanism is naturally implemented. We also study direct pair production of such right-handed sneutrinos at the Large Hadron Collider (LHC) and its decay modes, emphasising that their decay into same-sign di-lepton pairs are salient features for probing these particles at the CERN machine. Also, the charge asymmetry present in such same-sign di-lepton signals is analysed. We also study the single eld in ation in the context of supergravity with shift symmetry where the in aton arises from a charged sector under a U(1) gauge symmetry. Both non-anomalous and anomalous (with Fayet-Iliopoulos term) U(1) are studied. We show that the non-anomalous U(1) scenario is consistent with data of the cosmic microwave background and recent astrophysical measurements. A possible kinetic mixing between U(1) and U(1)B􀀀L is considered in order to allow for natural decay channels of the in aton, leading to a reheating epoch. Upper limits on the reheating temperature thus turn out to favour an intermediate ( O(1013) GeV) scale B 􀀀 L symmetry breaking. The problem of moduli stabilization in type IIB superstring theories is analyzed. We focus on the KKLT and Large Volume Scenario (LVS).We show that the predicted xv xvi soft SUSY breaking terms in KKLT model are not phenomenologically viable. In the LVS, the relic abundance of the lightest neutralino can not be consistent with the measured limits. We also study the cosmological consequences of moduli stabilization in both models. In particular, the associated in ation models such as racetrack in ation and K ahler in ation are analyzed. Finally the problem of moduli destabilization and the e ect of string moduli backreaction on the in ation models are discussed