Masses and widths of the rho(770)

M. Feuillat, J. L. Lucio M, J. Pestieau

Isospin violation in the $\rho (770)$ mass and width is considered within the $S$ matrix approach using combined fits to the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ and ${\tau }^{-}\to {\nu }_{\tau }{\pi }^{-}{\pi }^0$ data performed b…