The First Measurement of the - 0 Magnetic Moment

It has been known for a long time that the baryons cannot be point-like spin-l/2 particles like the electron and the muon. In the lowest mass baryon octet, containing p, n, ~+, ~0, ~ , A, ~0 and Z , the charged baryon magnetic moments differ considerably from their "natural" values, qBeh/2mB c, and, where they have been measured, the magnetic moments of the neutrals are of the same order of magnitude as the charged moments. The quark model predicts the baryon magnetic moments by a vector addition o f the moments of three constituent quarks (u, d, s), thus giving nine observables (all of the static/a's plus the transition moment responsible for the decay ~0 ~ AT) in terms of only three parameters:/a u,/.t d and/1 s *1. These three parameters can be calculated from measured values of tap,/s n and/a A [3]. Accurate measurements of the magnetic moments of the other baryons then furnish