Phases of resonant amplitudes: $\piN\rightarrow\pi\Lambda$

The phases of resonant amplitudes in pi N to pi Delta are studied in a modified version of SU(6)/sub W/ in which amplitudes involving different relative orbital angular momenta l are uncoupled from one another. This form of SU(6)/sub W/ is equivalent to one studied recently by Melosh, in which the set of selection rules for decays is extended to allow for more types of transition than in the original version of this symmetry. The predictions are compared with a recent preliminary analysis by Herndon et al. Even the extended ('l-broken') version of SU(6)/sub W/ is found to disagree with the present experimental solution. If this solution persists, it constitutes the strongest present evidence against such a symmetry. (22 refs).