Role of π in high-energy n--p charge exchange

The forward peak in n-p charge-exchange reactions is accounted for by a simple Born model. The value of the peak is shown to be due to u-channel π⁰ exchange, whereas its shape is found to be determined by the interference between the above mentioned π⁰ contribution and a π⁺ exchange in the t channel. The agreement with the data is fairly good for all incident momenta above 3 GeV/c and for a range of momentum transfer 0<|t|<0.005 (GeV/c)².