A Supersymmetric One Higgs Doublet Model

TL;DR

The paper introduces the Supersymmetric One Higgs Doublet Model (SOHDM), a minimal SUSY extension where only one Higgs doublet drives EWSB and fermion masses, aided by an anomaly-free R-symmetry and adjoint gaugino partners to realize Dirac masses. This framework suppresses proton decay, FCNCs, and CP violation, predicts a very light bino-like neutralino as the LSP, and uses low-scale SUSY breaking to naturally generate the μ-term and gaugino masses without requiring extra Higgs doublets. It also discusses neutrino masses via a seesaw mechanism, and outlines approaches to maintain perturbativity and gauge coupling unification, as well as distinctive collider signatures that could distinguish SOHDM from MSSM-like models. Overall, SOHDM offers a predictive, testable alternative to MSSM with reduced fine-tuning and characteristic LHC phenomenology.

Abstract

We present a supersymmetric extension of the Standard Model in which only one electroweak doublet acquires a vacuum expectation value and gives mass to Standard Model fermions. As well as the novel accommodation of a Standard Model Higgs within a supersymmetric framework, this leads to a very predictive model, with some advantages over the MSSM. In particular, problems with proton decay, flavour changing neutral currents and large CP violation are ameliorated, primarily due to the presence of an anomaly-free R-symmetry. Since supersymmetry must be broken at a low scale, gravity-mediated effects which break the R-symmetry are naturally small. The R-symmetry requires the presence of adjoint chiral superfields, to give Dirac masses to the gauginos; these adjoints are the only non-MSSM fields in the visible sector. The LSP is a very light neutralino, which is mostly bino. Such a light neutralino is not in conflict with experiment, and is a striking prediction of the minimal model. Additional scenarios to raise the mass of this neutralino to the weak scale are also outlined. Prospects for discovery at the LHC are briefly discussed, along with viable scenarios for achieving gauge-coupling unification.