Measurements of the differential cross sections of the pp --> pp pi(0) reac
tion at 310, 320, 340, 360, 400 and 425 MeV have been carried out at the CE
LSIUS storage ring in Uppsala. An attempt has been made to describe the dis
tributions obtained in terms of the five partial waves Ss, Ps, Pp, Sd and D
s. The relative contributions from the different; states depend significant
ly upon the energy For instance, that of the Ss state drops from about 80%
at 310 MeV to around 10% at 425 MeV.