Analog spin wave functions and spreading widths of isobaric analog resonances

The coupling of the isobaric analog state (IAS) to the giant isovector monopole state has been shown by Mekjian and Auerbach to dramatically affect the calculation of the spreading width. We show that the inclusion of this coupling is equivalent to a new definition of the IAS as an eigenstate of analog spin in which each proton radial wave function is distorted relative to the corresponding neutron radial wave functions by the central Coulomb field.