Collider bounds on 2-Higgs doublet models with U(1) X gauge symmetries

摘要

2-Higgs Doublet Models (2HDMs) typically need to invoke an ad-hoc discrete symmetry to avoid severe flavor bounds and in addition feature massless neutrinos, thus falling short of naturally complying with existing data. However, when augmented by an Abelian gauge symmetry naturally incorporating neutrino masses via a type-I seesaw mechanism while at the same time escaping flavor changing interactions, such enlarged 2HDMs become very attractive phenomenologically. In such frameworks, the distinctive element is theZ′gauge boson generated by the spontaneous breaking of the Abelian groupU(1)X. In this work, we derive updated collider bounds on it. Several theoretical setups are possible, each with different and sometimes suppressed couplings to quarks and leptons. Thus, complementary data from dijet and dilepton resonance searches need to be considered to fully probe these objects. We employ the corresponding datasets as obtained at the Large Hadron Collider (LHC) at the 13 TeV CMs energy forL=12, 36 and 300 fb?1of luminosity. Moreover, we present the potential sensitivity to suchZ′s of the High Luminosity LHC (HL-LHC) and High Energy LHC (HE-LHC).