Higgs decay to fermion pairs at NLO in SMEFT

TL;DR

This paper calculates NLO corrections from dimension-6 SMEFT operators to Higgs decays into various fermion pairs, enhancing precision and sensitivity to new physics in these processes.

Contribution

It extends previous SMEFT calculations of Higgs decays to include all relevant fermion channels at NLO, enabling more comprehensive future analyses.

Findings

NLO corrections for h→μμ, ττ, cc decays are computed.

Ratios of decay rates reveal increased sensitivity to anomalous couplings.

Results support precision tests of the Standard Model and new physics searches.

Abstract

The calculation of next-to-leading order (NLO) perturbative corrections at fixed operator dimension in Standard Model Effective Field Theory (SMEFT) has been a topic of much recent interest. In this paper we obtain the NLO corrections from dimension-6 operators to the Higgs boson decays $h\to f\bar{f}$, where the fermions $f \in \{\mu,\tau,c\}$. This extends previous results for $h\to b\bar{b}$ to all phenomenologically relevant Higgs boson decays into fermions, and provides the basis for future precision analyses of these decays within effective field theory. We point out the benefits of studying ratios of decay rates into different fermions in SMEFT, the most surprising of which is enhanced sensitivity to anomalous $h\gamma\gamma$ and $hgg$ couplings induced by flavor-universal SMEFT operators, especially in scenarios where flavor-dependent Wilson coefficients are constrained by Minimal Flavor Violation.