Production of the 1S0 diproton in the pp -> pp pi0 reaction at 0.8 GeV

Dymov, S.; Gusev, D.; Hartmann, M.; Hejny, V.; Kacharava, A.; Khoukaz, A.; Komarov, V.; Kulessa, P.; Kulikov, A.; Kurbatov, V.; Lang, N.; Macharashvili, G.; Mersmann, T.; Merzliakov, S.; Mikirtytchiants, S.; Mussgiller, A.; Prasuhn, D.; Rathmann, F.; Schleichert, R.; Stroeher, H.; Uzikov, Yu.; Wilkin, C.; Yaschenko, S.

Production of the 1S0 diproton in the pp -> pp pi0 reaction at 0.8 GeV

Authors

Description

The pp -> pp pi0 differential cross section has been measured with the ANKE spectrometer at COSY-Juelich for pion cms angles between 0 and 15.4 degrees at a proton beam energy of 0.8 GeV. The selection of diproton pairs with an excitation energy E_{pp} < 3 MeV ensures that the final pp system is dominantly in the spin-singlet 1S0 state. The kinematics are therefore very similar to those of pp -> d pi+ but with different spin and isospin transitions. The results will thus provide a crucial extra test of pion production models in nucleon-nucleon collisions. The cross sections, which are over two orders of magnitude smaller than those of pp -> d pi+, show a forward dip, even stronger than that seen at lower energies. This behaviour is well reproduced in a theoretical model that includes P-wave Delta-N states.
10 pages, 5 eps figures, prepared using elsart.cls