4 papers
The role of the input in Roy's equations for pion-pion scattering
G. Wanders
The Roy equations determine the S- and P-wave pion-pion phase shifts on a low energy interval. They allow the derivation of threshold parameters from experimental data. We examine…
One-channel Roy equations revisited
J. Gasser, G. Wanders
The Roy equation in the single channel case is a nonlinear, singular integral equation for the phase shift in the low-energy region. We first investigate the infinitesimal neighbor…
Chiral two-loop pion-pion scattering parameters from crossing-symmetric constraints
G. Wanders
Constraints on the parameters in the one- and two-loop pion-pion scattering amplitudes of standard chiral perturbation theory are obtained from explicitly crossing-symmetric sum ru…
Determination of the chiral pion-pion scattering parameters: a proposal
G. Wanders
An explicitly crossing-symmetric decomposition of the pion-pion scattering amplitudes into low- and high-energy components is established. The high-energy components are entirely d…