Chiral three-nucleon forces from p-wave pion production

Production of p-wave pions in nucleon-nucleon collisions is studied accordi ng to an improved power counting that embodies the constraints of chiral sy mmetry. Contributions from the first two nonvanishing orders are calculated . We find reasonable convergence and agreement with data for a spin-triplet cross section in pp --> pp pi(0), with no free parameters. Agreement with existing data for a spin-singlet cross section in pp --> pn pi(+) constrain s a short-range operator shown recently to contribute significantly to the three-nucleon potential.