Search for Structure in the γ-Ray Spectra from p¯d and p¯p Annihilations at Rest

Abstract

The $\gamma$-ray spectra from annihilations at rest have been measured with a 10-in.×10-in.-diam NaI(Tl) detector. The resolution of the system was ∼ 15% for $\gamma$-ray energies between 50 and 200 MeV. No clear evidence is found for monoenergetic $\gamma$ rays with intensities greater than 1 per 30 annihilations.