On the width of N-Delta and Delta-Delta states

TL;DR

This paper demonstrates that the decay width of N-Delta and Delta-Delta states is significantly reduced due to kinetic and angular momentum effects, impacting the interpretation of certain nuclear resonances.

Contribution

It provides a coupled-channel calculation showing how kinetic energy and angular momentum barriers decrease the widths of N-Delta and Delta-Delta states, including the d'(2380) resonance.

Findings

Width reduction due to kinetic energy effects

Angular momentum barrier further decreases width

Double-Delta width can be smaller than single Delta width

Abstract

It is seen by a coupled-channel calculation that in the two-baryon N-Delta or Delta-Delta system the width of the state is greatly diminished due to the relative kinetic energy of the two baryons, since the internal energy of the particles, available for pionic decay, is smaller. A similar state dependent effect arises from the centrifugal barrier in N-Delta or Delta-Delta systems with non-zero orbital angular momentum. The double-Delta width can become even smaller than the free width of a single Delta. This has some bearing to the interpretation of the d'(2380) resonance recently discovered at COSY.