2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198942Production of p-wave pions in nucleon-nucleon collisions is studied according to an improved power counting that embodies the constraints of chiral symmetry. Contributions from the first two non-vanishing orders are calculated. We find reasonable convergence and agreement with data for a spin-triplet cross section in $pp\to ppπ^0$,with no free parameters. Agreement with existing data for a spin-singlet cross section in $pp\to pnπ^+$ constrains a short-range operator shown recently to contribute significantly to the three-nucleon potential.4 pages, 3 figuresNuclear Theorytext