ISSN - 03702693, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 1998, vol. 436, p. 251-256
Pionic D-wave effects in pp → ppπ0 near threshold
The angular distribution of neutral pions produced in the pp → ppπ0 reaction has been measured at a beam energy of 310 MeV. Significant deviations from isotropy are found, which increase for small excitation energies of the final proton-proton pair. The results imply that d-wave pion production is important, even close to threshold. The parameter deduced for this is in quantitative agreement with data taken at very low excitation energy but various beam energies. Evidence is also presented for some P-wave excitation in the final proton-proton system. © 1998 Elsevier Science B.V. All rights reserved.