Pion exchange and the universal impact parameter hypothesis

In order to describe pion exchange reactions a modification to the 'b-universality' hypothesis is proposed which simply relates the impact parameter profiles of helicity amplitudes for different values of net helicity-flip. This proposal is shown to give an excellent quantitative fit to the π-p→rho0n and π-p→f0n data at 17.2 GeV/c. It also provides a natural explanation for the presence and size of the necessary absorptive cut corrections. (Auth.)