Analysis of hard two-photon correlations measured in heavy-ion reactions at intermediate energies

Analysis of hard two-photon correlations
measured in heavy-ion reactions at intermediate energies

H.W.Barz^1,2, B.Kämpfer^1,2, GY. Wolf^3,4, W. Bauer⁵

¹Institut für Kern- und Hadronenphysik, FZ Rossendorf,
PF 510119, 01314 Dresden, Germany
¹Institut für Theoretische Physik, TU Dresden,
Momrnsenstr. 13, 01062 Dresden, Germany
³GSI Darmstadt, PF 110552, 64220 Darmstadt, Germany
⁴KFKI RMKI Budapest, POB. 49, H-1525 Budapest, Hungary
MSU Michigan, East Lansing, MI 48824, USA

Abstract

Recently reported measurements of hard photon correlations in the reactions ³⁶Ar On ²⁷Al at 95 A*MeV, ⁸⁶Kr on ^natNi at 60 A*MeV, and ¹⁸¹Ta on ¹⁹⁷Au at 39.5 A*MeV are analyzed. A Boltzmann-Ühling-Uhlenbeck transport model is used to describe the photon production by individual nucleon-nucleon collisions. In the lighter systems we find the best agreement with data when taking into account only the photons from first chance collisions of nucleons or photons produced during the Passage of the nuclei, while the model predicts also a considerable late-time emission of photons which leads to a depletion of the calculated correlation function. The accuracy of the present data daas not allow firm conclusions on the reliability of this late time evolution. Our inveatigatiions do not support a recently reported interference pattern in the heavy Ta + Au system.