Determination of theΔ++−Δ0mass difference

The 3-3 phase shift obtained from ${\pi }^{+}p$ and ${\pi }^{-}p$ scattering is used to determine the positions of the poles in the $S$ matrix corresponding to the ${\Delta }^{++}$ and the ${\Delta }^0$. The mass difference is then given by the separation of these poles.