Higgs Yukawa coupling constraints on a benchmark one-loop radiative mass model for the bottom, charm and tau

TL;DR

This paper explores a radiative mass model for fermions that aligns with current Higgs coupling measurements, demonstrating its viability and the challenge of experimentally distinguishing it from the Standard Model, while also providing a dark matter candidate.

Contribution

The authors develop a benchmark one-loop radiative mass model for fermions, analyzing its compatibility with Higgs data and dark matter constraints, highlighting the difficulty of experimentally confirming the Standard Model mechanism.

Findings

Model fits current Higgs coupling measurements.

Future measurements will only raise the new physics scale, not exclude the model.

Dark matter candidate within the model reproduces observed relic density.

Abstract

Measurements of Higgs boson Yukawa couplings to Standard Model (SM) fermions constrain radiative mass models for those species. Such models, motivated by the observed fermion mass hierarchy, act as foils for the SM tree-level mechanism: we cannot claim to have verified the standard mechanism if other possibilities also fit the data well. We construct a benchmark model which generates the top mass at tree level, and the bottom, charm, tau, and tau Dirac neutrino masses at one-loop level. Current theoretical and experimental constraints on the model, including from Higgs decays, demonstrate it possesses viable regions of parameter space. We show that future improvements to measurements will not be able to rule out the model, only increase the scale of new physics required, illustrating how difficult it will be to verify the SM fermion mass generation mechanism with great precision. As a bonus, a dark matter candidate is shown to be capable of reproducing the correct relic density within the permitted parameter space.