The role of five-quark components in gamma decay of the Δ(1232)

An admixture of 10–20% of components in the Δ(1232) resonance is shown to reduce the well known underprediction by the qqq quark model of the decay width for Δ(1232)→Nγ decay by about half and that of the corresponding helicity amplitudes from a factor ∼1.7 to ∼1.5. The main effect is due to the quark–antiquark annihilation transitions: , the consideration of which brings the ratio A3/2/A1/2 and consequently the E2/M1 ratio REM into agreement with the empirical value. Transitions between the components in the resonance and the nucleon: , are shown to enhance the calculated decay width by only a few percent, as long as the probability of the component of the proton and the Δ(1232) is at most 20%. The transitions between the components in the Δ(1232) and the proton do not lead to a nonzero value for REM.