Verify that the potential $V(\pi, \sigma)$ can be written as Eq. (33.11), and that if $\epsilon=0$ and the symmetry is implemented in the Wigner mode the masses for the $\pi$ and $\sigma$ fields are degenerate and given by Eq. (33.13). A constant term may be discarded from a Lagrangian density without affecting physical quantities.

Data from Eq. 33.11

Data from Eq. 33.13

V(,) = ( + - v) - E + ). 2 1 + +