A new measurement of the pbar p -> nbar n charge-exchange differential cross-section at LEAR

We have measured the View the pbar p → nbar n charge-exchange differential cross-section at two incoming momenta (601.5 and 1202 MeV/c) at the CERN Low Energy Antiproton Ring. After reviewing the experimental method, the data analysis is fully detailed, and the results on the whole statistics available in the centre of mass forward hemisphere are given. A precision in the absolute normalisation of 2% and 4% at 601.5 and 1202 MeV/c respectively is achieved, while over most of the angular range the point-to-point error is lower than 1%. The forward peak associated with the nearby pion pole and a dip-bump structure are accurately measured. The “Chew” extrapolation to the pion-pole suggests a “low” value for the πNN coupling constant gc2.