<i>180°</i>-correlated equal-energy photons from 5.9-MeV/nucleon U + Th collisions

K. Danzmann; W. E. Meyerhof; E. C. Montenegro; Xiang-Yuan Xu; E. Dillard; H. P. Hülskotter; F. S. Stephens; R. M. Diamond; M. A. Deleplanque; A. O. Macchiavelli; J. Schweppe; R. J. McDonald; B. S. Rude; J. D. Molitoris

doi:10.1103/PhysRevLett.59.1885

180°-correlated equal-energy photons from 5.9-MeV/nucleon U + Th collisions

K. Danzmann, W. E. Meyerhof, E. C. Montenegro, Xiang-Yuan Xu, E. Dillard, H. P. Hülskotter, F. S. Stephens, R. M. Diamond, M. A. Deleplanque, A. O. Macchiavelli, J. Schweppe, R. J. McDonald, B. S. Rude, and J. D. Molitoris

Phys. Rev. Lett. 59, 1885 – Published 26 October 1987

Abstract

We have found a narrow line (intrinsic width ≤2.5 keV) at 1062±1 keV in the summed-energy 180°-c.m.-correlated two-photon spectrum from 5.95-MeV/nucleon U+Th collisions. Including possible systematic uncertainties, the production cross section is found to be 50±25 μb, averaged over the 1-mg/ ${cm}^{2}$ Th target thickness. This line may belong to the decay of a neutral system which also produces correlated electron-positron pairs found by others in the same reaction.