Emission of 8Li, 9Li and 8B Fragments from Stars Produced by 4.3 Gev π--Mesons in Nuclear Emulsion

Abstract

9.300 stars with more than 5 black prongs were examined to study ⁸ Li, ⁹ Li and ⁸ B fragments emitted from these stars. Thus, we found 90 examples of hammer tracks produced by ⁸ Li or ⁸ B fragments, 11 examples of tracks produced by ⁹ Li→ ⁹ Be+ e ^- → ⁴ He+ ⁴ He+ n + e ^- and the one by ⁹ Li→ ⁹ Be+ e ^- → ⁵ He+ ⁴ He+ e ^- . The experimental result of angular distribution, energy distribution, and frequency of emission of these fragments are given. Comparison is made between the experimental result and the prediction of evaporation theory on the frequency of emission of these fragments. The effect of the ⁸ B fragments on the estimation of the Coulomb barrier of the residual nucleus for ⁸ Li fragment is discussed.