Abstract: This paper, the second of a series on the subject, is entirely devoted to the pion-pion scattering amplitude. The main results are: 1) The scattering amplitude can be continued till the border-line of the double-spectral function, except for\(8\mu ^2< s< 32\mu ^2 \). Hence the nearest singularities are really induced by two-particle unitarity. Another consequence is that the only possible static potential describing low-energy pion-pion scattering is a Yukawa superposition. The domain of validity of fixed-transfer dispersion relations is slight...
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Topics: 
Mathematical physics
Quantum mechanics
Quantum electrodynamics