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

An admixture of 10-20% of qqqqq-bar 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: qqqqq-bar ->qqqγ, 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 qqqqq-bar components in the resonance and the nucleon: qqqqq-bar ->qqqqq-bar γ, are shown to enhance the calculated decay width by only a few percent, as long as the probability of the qqqqq-bar component of the proton and the Δ(1232) is at most 20%. The transitions qqqqq-bar ->qqqqq-bar γ between the qqqqq-bar components in the Δ(1232) and the proton do not lead to a nonzero value for REM