Pion production in nucleon-nucleon collisions in chiral effective field theory: next-to-next-to-leading order contributions

A. A. Filin, V. Baru, E. Epelbaum +4

A complete calculation of the pion-nucleon loops that contribute to the transition operator for $NN\to NN\pi$ up-to-and-including next-to-next-to-leading order (N${}^2$LO) in chiral ef…