2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/199020We discuss the results of a systematic calculation of the next-to-next-to-leading order amplitude for the pp -> ppπ^0 S-wave production at the threshold in heavy-baryon chiral perturbation theory. We find six new diagrams, two of which can be viewed as vertex corrections, of 15 - 20 %, to the pion-exchange graph, whereas the rest are much larger, one exceeding 900 %. We discuss the reasons for this enhancement, as well as the steps necessary to be taken before the final comparison with experiment.4 pages, 2 figures, talk delivered at PANIC99, correction of column VII in Table 1 and corresponding change of one sentence in the text on p.3Nuclear Theorytext