Standard Model in adS slice with UV-localized Higgs field

TL;DR

This paper explores a five-dimensional AdS model with a UV-localized Higgs, addressing fermion mass hierarchies, quark mixings, and neutrino masses, while highlighting constraints from flavor-changing neutral currents.

Contribution

It introduces a model where fermion masses and mixings are generated without small Yukawas, and analyzes the implications of KK excitations on flavor physics and neutrino masses.

Findings

Fermion mass hierarchy achieved without tiny Yukawa couplings

FCNC processes impose strong constraints on KK mass scale

Neutrino mass generation via Higgs KK modes is subdominant

Abstract

We discuss five-dimensional Standard Model in a slice of adS space-time with the Higgs field residing near or on the UV brane. Allowing fermion fields to propagate in the bulk, we obtain the hierarchy of their masses and quark mixings without introducing large or small Yukawa couplings. However, the interaction of fermions with the Higgs and gauge boson KK excitations gives rise to FCNC with no built-in suppression mechanism. This strongly constrains the scale of KK masses. We also discuss neutrino mass generation via KK excitations of the Higgs field. We find that this mechanism is subdominant in the scenarios of spontaneous symmetry breaking we consider.