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Abstract

Motivated by the fermion mass hierarchy we study the phenomenology of two
flavorful two-Higgs-doublet model (2HDM) scenarios. By virtue of the flavor or
singular alignment ansatz it is possible to link the mass of a subset of
fermions to the vacuum-expectation-value (VEV) of a unique Higgs doublet and to
simultaneously avoid flavor-changing-neutral-currents at tree-level. We
explicitly construct two models called Type-A and B. There, either the top
quark alone or all third generation fermions couple to the doublet with the
larger VEV. The other fermions acquire their masses through the small VEV of
the other doublet. Thus, more natural values for the Yukawa couplings can be
obtained. The main differences between these models and conventional ones are
studied including a discussion of both their structure and phenomenological
consequences. In particular, as distinctive deviations for the Yukawa couplings
of the light fermions are predicted we discuss possible tests at the LHC based
on searches for $h\to J/\Psi + \gamma$, $h\to\mu\mu$, and heavy scalar
resonances decaying to muon pairs. We find that for a wide region of parameter
space this specific set of signatures can be used to distinguish among the new
proposed types and the conventional ones.