  CERN measurements of pi(-)p->pi(-)pi(+)n on polarized target at 17.2 GeV/c
enable experimental determination of partial wave production amplitudes below
1080 MeV. The measured S-wave transversity amplitudes provide evidence for a
narrow scalar resonance sigma(770). The assumption of analyticity of production
amplitudes in dipion mass allows to determine S-wave helicity amplitudes S_0
and S_1. The amplitude S_1 is related to pi(-)pi(+)->pi(-)pi(+) scattering.
There are four "down" solutions (1, 1bar), (2, 1bar), (1, 2bar) and (2, 2bar)
selected by unitarity in pipi scattering. Ellis-Lanik relation between the mass
m_sigma and partial width Gamma(sigma->pi(-)pi(+)) derived from an effective
QCD theory with broken scale and chiral symmetry selects solutions (1, 1bar)
and (1, 2bar) and imparts the sigma(770) resonance with a dilaton-gluonium
interpretation. Weinberg's mended symmetry selects solutions (1, 1bar) and (2,
1bar). The combin ed solution (1, 1bar) has m_sigma=769 +/- 13 MeV and
Gamma_sigma=154 +/- 22 MeV. The observed sigma-rho^0 degeneracy leads to two
new relations between gluon condensate and pion decay constant and SU(2) chiral
condensate. Both relations are well satisfied. Ellis-Lanik relation relates the
existence of sigma(770) to breaking of scale symmetry in QCD. Interaction of
chirally invariant and narrow sigma(770) with a chirally noninvariant QCD
vacuum in pi(-)pi(+)->pi(-)pi(+) scattering is proposed as a possible mechanism
for the metamorphosis of sigma(770) into a broad resonant S-wave structure in
pi(-)pi(+)->pi(-)pi(+) related to spontaneous breaking of chiral symmetry in
QCD.
