Mass and width of the d' resonance in nuclei

We calculated the mass and width of the d' resonance inside nuclei within a nucleon-Δ model by including the self-energy of the Δ in the NΔ propagator. We found that in the nuclear medium the width of the d' is increased by 1 order of magnitude while its mass changes only by a few MeV. This broadening of the width of the d' resonance embedded in nuclei is consistent with the experimental observations so that the d' can be understood as a NΔ resonance. Thus, given the freedom between either isospin 0 or isospin 2 for the d', our results give weight to the isospin-2 assignment. copyright 1996 The American Physical Society