It has been shown by other workers that some of the fragments of relativistic heavy-ion collisions have an anomalously short interaction length but may revert to normal nuclei within ∼${10}^{-11\mathrm{}}$ sec. Lead-glass detectors were used to search for delayed high-energy $\gamma$ rays emitted from projectile fragments of 940-MeV/u ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ interactions with a steel target. The present negative result casts doubt on some recent models in which anomalous states decay electromagnetically to normal nuclei.

• Received 1 June 1982

DOI:https://doi.org/10.1103/PhysRevLett.49.775