On the magnitude of the Li-8+He-4 -> B-11+n reaction cross section at the Big-Bang temperature

The Li-8 + He-4 -> B-11 + n reaction at E-cm < 2 MeV is a process of relevant astrophysical interest for which a remarkable experimental discrepancy between inclusive and exclusive cross-section measurements exists. In this Letter, a new inclusive neutron measurement at E-cm = 1.05 +/- 0.16 MeV is given. The radioactive Li-8 beam was delivered by the EXCYT facility. The cross section was determined by a low-background measurement of the time correlation between the Li-8 projectile arrival to the target and the following neutron capture in a threshold-less 4 pi thermalization counter. This new data strengthens the reliability of the previous inclusive reaction cross-section data and altogether are consistent with a significant population of B-11 levels at high excitation energy. (c) 2008 Elsevier B.V. All rights reserved.