Effective field theory calculations of NN → NNπ

In this review, we present the recent advances for calculations of the reactions NN -> NN pi using chiral effective field theory chi EFT. Discussed are the next-to-next-to leading order ((NLO)-L-2) loop contributions with nucleon and Delta-isobar for near threshold s-wave pion-production. Results of recent experimental pion-production data for energies close to the threshold are analyzed. Several particular applications are discussed: (i) it is shown how the measured charge symmetry (CS) violating pion-production reaction can be used to extract the strong interaction contribution to the proton-neutron mass difference; (ii) the role of NN -> NN pi for the extraction of the pion-nucleon scattering lengths from pionic atoms data is illuminated.