ΔI = 1 axial-vector mixing and charge symmetry breaking

Phenomenological Lagrangians that exhibit (broken) chiral symmetry as well as isospin violation suggest short-range charge symmetry breaking (CSB) nucleon-nucleon potentials with a σ1 · σ2 structure. This structure could be realized by the mixing of axial-vector (1+) mesons in a single-meson exchange picture. The Coleman-Glashow scheme for ΔIz = 1 charge symmetry breaking applied to meson and baryon SU(2) mass splittings suggests a universal scale. This scale can be extended to ΔI = 1 nonstrange CSB transitions 〈a1o|Hem|f1〉 of size −0.005 GeV2. The resulting nucleon-nucleon axial-vector meson exchange CSB potential then predicts ΔI = 1 effects which are small.