Flavour Changing Higgs Couplings in a Class of Two Higgs Doublet Models

TL;DR

This paper investigates flavor-changing neutral currents in a specific class of two Higgs doublet models, showing potential for observable signals at the LHC while remaining consistent with low-energy constraints.

Contribution

It introduces a natural, stable flavor structure in two Higgs doublet models where flavor-changing couplings are determined by CKM, PMNS matrices, and 2, and analyzes their potential observability.

Findings

Flavor-changing processes can reach LHC discovery levels.

Models' flavor structure is stable under renormalization.

Constraints from low-energy processes are satisfied.

Abstract

We analyse various flavour changing processes like $t\to hu,hc$, $h\to \tau e,\tau\mu$ as well as hadronic decays $h\to bs,bd$, in the framework of a class of two Higgs doublet models where there are flavour changing neutral scalar currents at tree level. These models have the remarkable feature of having these flavour-violating couplings entirely determined by the CKM and PMNS matrices as well as $\tan\beta$. The flavour structure of these scalar currents results from a symmetry of the Lagrangian and therefore it is natural and stable under the renormalization group. We show that in some of the models the rates of the above flavour changing processes can reach the discovery level at the LHC at 13 TeV even taking into account the stringent bounds on low energy processes, in particular $\mu\to e\gamma$.