NLO radiative corrections for forward-backward and left-right asymmetries at a B -factory

This paper presents the first calculations of the parity-violating polarization asymmetry and forward-backward asymmetry of the e⁺e^-→μ⁺μ^-(γ ) process at a center-of-mass energy of 10.579 GeV with up to one-loop electroweak radiative corrections. The calculations are relevant for future precision electroweak measurements at the Belle II experiment, which is now collecting data at the SuperKEKB e⁺e^- collider with a center-of-mass energy at the mass of the ϒ (4 S ) resonance. In this paper we take under full control the bremsstrahlung process at the conditions of Belle II/SuperKEKB, and the possibilities for a soft photon approach are discussed. The scale of the obtained relative corrections to the parity-violating and forward-backward asymmetries is significant and the scattering angle dependencies of the asymmetries is nontrivial. As an additional validation cross-check using an independent formulation, the calculated asymmetries are compared to results from the K K Monte Carlo generator.