Speaker
Description
The radiative capture reaction 𝛼(d, 𝛾)6Li plays an important role in the early-Universe production of lithium and other light nuclei and has therefore been subject to extensive experimental and theoretical investigations. Its cross section was measured directly in the range of astrophysical relevance for the first time in 2014 by the LUNA collaboration [1]. Earlier two attempts to determine the cross section indirectly via Coulomb dissociation were performed as this process can be understood as the time reversed process of radiative captures [2,3]. With a fully dynamical reaction model, we report here on a new theoretical analysis of these Coulomb dissociation experiments. Our results indicate that the breakup of 6Li onto 208Pb at 150 A MeV and 26 A MeV is characterized by marked Coulomb-nuclear interferences. Moreover, the analysis points towards a nuclear dominated process at forward angles as Coulomb breakup is suppressed due to the 𝛼-d clustered structure of 6Li. Furthermore, we confirm the relevance of higher-order effects in the breakup process. Consequently, extracting radiative capture cross sections from data at these energies is unfeasible. The forward Coulomb breakup suppression may be a general feature of breakup processes involving N=Z clustered nuclei. We underscore the importance of alternative indirect methods for the determination of cross sections for astrophysics such as photodissociation induced by electrons.
[1] M. Anders et al. (LUNA Collaboration), Phys. Rev. Lett., 113, 042501 (2014).
[2] J. Kiener et al., Phys. Rev. C, 44, 2195 (1991).
[3] F. Hammache et al., Phys. Rev. C, 82, 065803 (2010).