  Applying the effective amplitude, which is evidently consistent with general
constraints from chiral symmetry, the pipi spectra in the relevant processes
are analyzed, leading to a strong evidence for existence of the light sigma
meson. It is also pointed out that the pipi scattering process, which had been
one of the main sources for PDG table for these many years, is, in principle,
exceptionally difficult to investigate the property of sigma-meson.
