Multipole moments of spin 3 2 particles

The formalism for extracting electromagnetic form factors, and thus moltipole moments, of the SU(3)_flavor spin 3 2 baryon decuplet lattice hadronic correlation functions is presented. Results from the first such quenched lattice QCD calculation of magnetic moments, electric radii and magnetic radii are compared to the corresponding quantities calculated previously for the members of the spin 1 2 baryon octet. The lattice results give evidence of spin-dependent forces and center-of-mass effects in the quark electromagnetic properties. In contrast to the octet, these effects tend to cancel for the decuplet. Consequently, the deviations of the lattice baryon magnetic moments from the simple quark model predictions, while quite sizeable for the octet baryons, are seen to be much smaller for the decuplet baryons. Lattice predictions for the magnetic moments of the Ω^- and the Δ⁺⁺ are compared to recent experimental results. We have also calculated octet-decuplet transition. The first lattice results for the proton-delta transittion show a strong M1 signal which agrees well with a recent extraction of the moment from experimentally measured helicity amplitudes. A model-independent limit for the E2/M1 ratio is reported.