Rho-Like Mesons from Analysis of the Pion-Pion Scattering

Considering analyticity, unitarity and an influence of coupled channels, experimental data on the isovector P-wave of pion-pion scattering was analyzed to study rho-like mesons below 1900 MeV. The analysis indicates evidently that in the energy range 1200–1800 MeV, there are three rho-like mesons: rho(1250), rho(1450) and rho(1600), unlike the PDG tables. The obtained P-wave pion-pion scattering length (a_1^1=33.9± 2.02 [10^{-3}m_{pi^+}^{-3}]) most matches to the one calculated in the local Nambu–Jona-Lasinio model.