Dark NLO Correction to Dark Photon Production at Lepton Colliders

In this work, we calculate the inclusive cross-section for the single dark photon production process in an electron–positron collider up to next-to-leading order (NLO). The dark photon studied in this work is embedded in a more complete dark Abelian Higgs model charged under a spontaneously broken U(1)′ gauge symmetry. The breaking of U(1)′ generates the mass of the dark photon. The inclusive cross-section contains σ(e+e−→γA′) and σ(e+e−→γA′s), with A′/s being the dark photon/the dark Higgs, respectively. To remove the infrared (IR) divergence that appears at the high energy limit, virtual correction from the dark sector, which is the self-energy of dark photon, is also included. The cancellation of the IR divergences between the real correction and virtual correction makes the final NLO cross-section IR-safe. The phenomenological effect of this NLO correction is also briefly discussed.