Flavour-changing Higgs couplings in a class of two Higgs doublet models

Abstract

We analyse various flavour-changing processes like $$t\rightarrow hu,hc$$ , $$h\rightarrow \tau e,\tau \mu $$ as well as hadronic decays $$h\rightarrow bs,bd$$ , 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 renormalisation 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 $$\mu \rightarrow e\gamma $$ .