Roy's equations and the pion-pion experimental data
arXiv:hep-ph/0310082 · doi:10.1063/1.1799704
Abstract
Roy's equations are used to check if the scalar-isoscalar pion-pion scattering amplitudes fitted to experimental data fulfill crossing symmetry conditions. It is shown that the amplitudes describing the ``down-flat'' phase shift solution satisfy crossing symmetry below 1 GeV while the amplitudes fitted to the "up-flat'' data do not. In this way the long standing "up-down" ambiguity in the phenomenological determination of the scalar-isoscalar pion-pion amplitudes has been resolved confirming the independent result of the recent joint analysis of the pi+pi- and pi0pi0 data.
6 pages, 2 figures, talk given at Tenth International Conference on Hadron Spectroscopy (Hadron'03), Aschaffenburg, Germany, August 31 - September 6 2003