Minimal violation of flavour and custodial symmetries in a vectophobic Two-Higgs-Doublet-Model

TL;DR

This paper explores a vectophobic Two-Higgs-Doublet-Model that minimally violates flavour and custodial symmetries, potentially leading to observable effects in B_s decay and diphoton spectra at the LHC.

Contribution

It introduces a novel 2HDM framework with minimal symmetry violation, highlighting possible experimental signatures within current collider capabilities.

Findings

Potential enhancement in B_s→μ+μ− decay rate

Possible diphoton resonance around 125 GeV

Light, flavour-violating scalar effects within LHC reach

Abstract

Tree-level accidental symmetries are known to play a fundamental role in the phenomenology of the Standard Model (SM) for electroweak interactions. So far, no significant deviations from the theory have been observed in precision, flavour and collider physics. Consequently, these global symmetries are expected to remain quite efficient in any attempt beyond the SM. Yet, they do not forbid rather unorthodox phenomena within the reach of current LHC experiments. This is illustrated with a vectophobic Two-Higgs-Doublet-Model (2HDM) where effects of a light, flavour-violating and custodian (pseudo)scalar might be observed in the $B_s\to\mu^+\mu^-$ decay rate and in the diphoton invariant mass spectrum at around 125 GeV.