ETA PRODUCTION IN REACTION PIP-]PIPETA AT 1050-MEV/C AND 1170-MEV/C

We have investigated production in the reaction +p+p at 1050 and 1170 MeV/c, and in the reaction -p-p at 1170 MeV/c. We obtain the following partial cross sections for the reaction pp followed by the charged decay +-0:9.51.5 b for 1050-MeV/c incident +; 53.35.0 b for 1170-MeV/c -; 15.91.9 b for 1170-MeV/c -. From our + data we find that we need four I=32 amplitudes in order to obtain good agreement with our mass and angular distributions and to reproduce the threshold behavior of the cross section. We find the dominating amplitude to be that representing the reaction +p(1238), (1238)+p, where the and the (1238) are produced in s wave. The four amplitudes are extrapolated to higher energies where the predicted mass and angular distributions and cross sections are compared with the available data. From our - data we find that in addition to the four I=32 amplitudes (determined from the + data), one I=12 amplitude is required: the amplitude in which all particles are in relative S states. We find that this I=12 amplitude in fact dominates the - reaction. We see no evidence for production of an N*(1550)p resonance. We are able to parametrize the cross sections for pp from threshold to 4 BeV/c. © 1969 The American Physical Society.