In Ref. [1], a method was proposed to calculate QED corrections to hadronic self energies from lattice QCD without power-law finite-volume errors. In this paper, we extend the method to processes which occur at second-order in the weak interaction and in which there is a massless (or almost massless) leptonic propagator. We demonstrate that, in spite of the presence of the propagator of an almost massless electron, such an infinite-volume reconstruction procedure can be used to obtain the amplitude for the rare kaon decay K+→π+ννˉ from a lattice quantum chromodynamics computation with only exponentially small finite-volume corrections.
@article{arxiv.2009.08287,
title = {Finite-volume effects in long-distance processes with massless leptonic propagators},
author = {Norman H. Christ and Xu Feng and Lu-Chang Jin and Christopher T. Sachrajda},
journal= {arXiv preprint arXiv:2009.08287},
year = {2021}
}