Phenomenology of Z’ bosons at the LHC

• Juri Fiaschi

Room: Aula Seminari In this talk will be presented an updated overview on the searches for BSM heavy neutral resonances (usually called Z'-bosons) at LHC in the Run-II stage. Theoretically-inspired BSM models featuring a Z' boson will be introduced and their phenomenology will be explored in relation with the usual CMS and ATLAS groups experimental analysis. Some critical aspects of the latter will be discussed, motivating the introduction of extra observables and techniques to improve the sensitivity for both the detection and the diagnose of Z' signals, with particular focus on less conventional scenarios featuring large resonance widths and multiple resonant profiles.

E6-Inspired U(1)’-Extended MSSM: From Dark Matter to LHC

• Jack Yakup Araz

Room: Aula Seminari 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 realisations 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.

Dark Matter and collider signatures of extended Higgs sectors with or without CP violation

• Venus Keus

Room: Aula Seminari I will review popular minimal singlet and doublet scalar extensions of the Standard Model with viable Dark Matter candidates. After satisfying relic density conditions, these models are further constrained by direct and indirect detection experiments and by LHC data.  Moreover, if one introduces CP violation in the scalar sector, the bounds from Electric Dipole Moment experiments limit the model further. I will then motivate 3-Higgs-Doublet Models and show that such models can accommodate Dark Matter candidates and CP violation in the scalar sector simultaneously while surviving all experimental and theoretical bounds. I will then present "smoking gun" signatures of such models at the LHC.

On the way to future circular colliders: new physics opportunities with top quarks and Higgs bosons

• Benjamin Fuks

Room: Aula Seminari While LHC Run 2 operations are ongoing, it is timely to start considering the next phase of the high-energy collider program including both the LHC and future projects under discussion. In this context, I will follow a bottom-up path where the Standard Model Lagrangian is modified by several effective operators and investigate how studying the production of a pair of top-antitop quarks and three Higgs bosons could provide meaningful probes for deviations of from the Standard Model.