Five-quark components inΔ(1232)→Nπdecay

Abstract

Five-quark $\mathit{qqqq}\overline{q}$ components in the $\ensuremath{\Delta}(1232)$ are shown to contribute significantly to $\ensuremath{\Delta}(1232)\ensuremath{\rightarrow}N\ensuremath{\pi}$ decay through quark-antiquark annihilation transitions. These involve the overlap between the qqq and the $\mathit{qqqq}\overline{q}$ components and may be triggered by the confining interaction between the quarks. With a ~10% admixture of five-quark components in the $\ensuremath{\Delta}(1232)$ the decay width can be larger by factors ~2 -- 3 over that calculated in the nonrelativistic quark model with three valence quarks, depending on the details of the confining interaction. The effect of transitions between the $\mathit{qqqq}\overline{q}$ components themselves on the calculated decay width is however small. The large contribution of the quark-antiquark annihilation transitions thus may compensate the underprediction of the width of the $\ensuremath{\Delta}(1232)$ by the valence quark model, once the $\ensuremath{\Delta}(1232)$ contains $\mathit{qqqq}\overline{q}$ components with ~10% probability.