Five-quark components in $\Delta (1232)\to N\pi$ decay

Abstract

Five-quark $qqqq\bar{q}$ components in the $\Delta (1232)$ are shown to contribute significantly to $\Delta (1232)\to N\pi$ decay through quark-antiquark annihilation transitions. These involve the overlap between the $qqq$ and $qqqq\bar{q}$ components and may be triggered by the confining interaction between the quarks. With a $\sim$ 10% admixture of five-quark components in the $\Delta (1232)$ the decay width can be larger by factors 2 - 3 over that calculated in the quark model with 3 valence quarks, depending on the details of the confining interaction. The effect of transitions between the $qqqq\bar{q}$ 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 $\Delta (1232)$ by the valence quark model, once the $\Delta (1232)$ contains $qqqq\bar{q}$ components with $\sim$ 10% probability.

Comments: accepted version