When an error in earlier work is corrected, it is shown that the requirements of $t$-channel unitarity do not affect the validity of the extrapolation procedure of Cheng and Dashen. This conclusion also holds in an extension of our earlier analysis to the case where the $\sigma$ field transforms as a member of the ($\frac{N}{2}$) representation of chiral SU(2) × SU(2).

• Received 19 June 1972

DOI:https://doi.org/10.1103/PhysRevD.6.1801