Violations of SU(6) Selection Rules from Quark Hyperfine Interactions

The decay amplitudes for D₁₅→pγ, the amplitude for D₀₅→K̄N, and the charge radius of the neutron are zero in the SU(6) limit, but are observed to be nonzero. We show that all of these SU(6)-violating effects can be understood quantitatively in terms of the admixtures of excited-state configurations in the nucleon expected on the basis of color hyperfine interactions. In particular, the admixture of ²SM (i.e., [70, 0⁺]) with an amplitude of about - {} is central to understanding all three effects.