Flavour alignment in multi-Higgs-doublet models

Understand

Extended electroweak scalar sectors containing several doublet multiplets require flavour-aligned Yukawa matrices to prevent the appearance at tree level of unwanted flavour- changing neutral-current transitions.

• We analyse the misalignment induced by one-loop quantum corrections and explore possible generalizations of the alignment condition and their compatibility with current experimental constraints.
• The hypothesis of flavour alignment at a high scale turns out to be consistent with all known phenomenological tests.