Higgs decay to two photons at one-loop in the SMEFT
Christine Hartmann, Michael Trott
TL;DR
This paper computes the CP-conserving, dimension-six one-loop contributions to the Higgs decay rate into two photons within the linear SMEFT framework, using a background-field method and a complete operator basis. It provides the renormalization structure, distinguishes direct and indirect SMEFT effects, and derives explicit one-loop corrections to the h→γγ amplitude, including scheme-dependent pieces and mappings to SM loop functions. Numerically, the results show that SMEFT loop effects can significantly alter the interpretation of current and future experimental bounds on the decay, sometimes shifting inferred Wilson-coefficient limits by large percentages depending on the new physics scale. The findings stress the importance of incorporating these loop corrections in precision Higgs analyses and offer a template for loop-improving other SMEFT processes.
Abstract
We present the calculation of the $\rm CP$ conserving contributions to $Γ(h \rightarrow γγ)$, from dimension six operators at one-loop order, in the linear Standard Model Effective Field Theory. We discuss the impact of these corrections on interpreting current and future experimental bounds on this decay.