H → τ + τ − γ as a probe of the τ magnetic dipole moment

Low energy observables involving the standard model fermions which are chirality-violating, such as anomalous electromagnetic moments, necessarily involve an insertion of the higgs in order to maintain su(2) × u(1) gauge invariance. as the result, the properties of the higgs boson measured at the lhc impact our understanding of the associated low-energy quantities. we illustrate this feature with a discussion of the electromagnetic moments of the τ -lepton, as probed by the rare decay h → τ + τ − γ. we assess the feasibility of measuring this decay at the lhc, and show that the current bounds from lower energy measurements imply that 13 tev running is very likely to improve our understanding of new physics contributing to the anomalous magnetic moment of the tau.