Complete next-to-next-to-leading order calculation of NN → NNπ in chiral effective field theory

Abstract

We present the results of the pion production operator calculated up-to-and-including next-to-next-to-leading order (NNLO) in chiral effective field theory. We include explicit Delta degrees of freedom and demonstrate that they provide essential contribution required to understand neutral pion production data. Analysis of chiral loops at NNLO reveals new mechanisms which are important, but haven’t been considered in phenomenological studies so far.