Dark photon effect on the rare kaon decay K-L -> pi(0) nu(nu)over-bar

We present an analysis of the effect of a dark photon on the rare kaon decay K-L -> pi(0) nu(nu) over bar. All relevant couplings of the dark photon to the standard model particles are derived explicitly in terms of the dark photon mass and the mixing parameter. We find that the dark photon yields no more than a few percent correction to the standard model branching ratio Br(K-L -> pi(0) nu(nu) over bar) in the region of interest.

Automated summary

We analyze the impact of a dark photon on the rare kaon decay K-L -> pi(0) nu(nu) over bar. The couplings between the dark photon and standard model particles are derived explicitly in terms of the dark photon mass and mixing parameter. We find that the dark photon correction to the standard model branching ratio Br(K-L -> pi(0) nu(nu) over bar) is no more than a few percent in the relevant region.