Proposal to observe the strong Van der Waals force in e+e -> 2 π

الأصل · EN

Large discrepancy of the p-wave phase shift data δ₁(ν) of the π-π scattering from those of the dispersion calculation is pointed out. In order to determine which is correct, the pion form factor Fπ(ν), which is the second source of information of the phase shift δ₁(ν), is used. It is found that the phase shift obtained from the dispersion is not compatible with the data of the pion form factor. What is wrong with the dispersion calculation, is considered.