Hard photons in heavy-ion collisions: Direct or statistical?

N. Herrmann; R. Bock; H. Emling; R. Freifelder; A. Gobbi; E. Grosse; K. D. Hildenbrand; R. Kulessa; T. Matulewicz; F. Rami; R. S. Simon; H. Stelzer; J. Wessels; P. R. Maurenzig; A. Olmi; A. A. Stefanini; W. Kühn; V. Metag; R. Novotny; M. Gnirs; D. Pelte; P. Braun-Munzinger; L. G. Moretto

doi:10.1103/PhysRevLett.60.1630

Hard photons in heavy-ion collisions: Direct or statistical?

N. Herrmann, R. Bock, H. Emling, R. Freifelder, A. Gobbi, E. Grosse, K. D. Hildenbrand, R. Kulessa, T. Matulewicz, F. Rami, R. S. Simon, H. Stelzer, J. Wessels, P. R. Maurenzig, A. Olmi, A. A. Stefanini, W. Kühn, V. Metag, R. Novotny, M. Gnirs, D. Pelte, P. Braun-Munzinger, and L. G. Moretto

Phys. Rev. Lett. 60, 1630 – Published 18 April 1988

Abstract

Photons with energies from 2 to 60 MeV have been measured in coincidence with binary fragments in the reaction ${}^{92}$ Mo $+^{92}$ Mo at an incident energy of 19.5A MeV. The rapid change of the γ-ray spectrum and multiplicity with the fragment total kinetic energy in the exit channel indicates that the γ rays are emitted statistically by the highly excited fragments. Temperatures as high as 6 MeV are inferred.