Symmetries for standard model alignment in multi-Higgs doublet models

Abstract

We derive the complete set of continuous maximal symmetries for standard model (SM) alignment that may occur in the tree-level scalar potential of multi-Higgs doublet models, with n>2 Higgs doublets. Our results generalize the symmetries of SM alignment, without decoupling of large mass scales or fine-tuning, previously obtained in the context of two-Higgs doublet models.