In multi-Higgs-doublet models, the alignment in flavour space of all Yukawa
matrices coupling to a given right-handed fermion guarantees the absence of
tree-level flavour-changing neutral couplings, while introducing new sources of
CP violation. With N Higgs doublets (and no right-handed neutrinos) the Yukawa
Lagrangian is characterized by the fermion masses, the CKM quark mixing matrix
and 3(N-1) complex couplings. Quantum corrections break the alignment,
generating a minimal-flavour-violation structure with flavour-blind phases. The
aligned multi-Higgs-doublet models lead to a rich and viable phenomenology with
an interesting hierarchy of flavour-changing neutral current effects,
suppressing them in light-quark systems while allowing potentially relevant
signals in heavy-quark transitions.Comment: 6 pages, 5 figures. Talk given in the "Third Workshop on Theory,
Phenomenology and Experiments in Heavy Flavour Physics" (Capri, 5-7 July
2010
