The MSSM has undoubtedly been a successful framework in terms of suggesting solutions to the unresolved shortcomings of the Standard Model such as Dark Matter, the Gauge hierarchy problem etc. However, the lack of evidence for Supersymmetry at the LHC motivates us to investigate extensions of the MSSM basic gauge group structure, with the hope of finding answers to these questions.
For this reason, we have studied a simple U(1)' extension of the MSSM group structure which can arise within the Grand Unified framework. We investigate scenarios in which either the right-handed sneutrino or the lightest neutralino are viable dark matter candidates and we explore the parameter space of different supersymmetric realizations featuring an extra U(1)'.
On the side of LHC phenomenology, searching for heavy Z' vector bosons predicted in such models is a challenging objective. The ATLAS and CMS collaborations have looked for such Z' bosons assuming that they can only decay into Standard Model channels, and have placed corresponding exclusion limits by considering dilepton, dijet and, to a smaller extent, top-antitop final states. Alongside with dark matter, we also explore possible loopholes in these Z' searches by studying supersymmetric as well as leptophobic scenarios and we proposed a possible way to probe leptophobic Z' via supersymmetric final states.