Dominance of the direct reaction process in the 12C( 7Li, 7Be) 12B reaction at θL=0° and [formula omitted

Abstract

The 12C( 7Li, 7Be) 12B reaction is studied at projectile energies of 14, 21 and 26 MeV/ A. Emitted 7Be particles are detected at θ L∼0° with an energy resolution of about 200 keV which is enough to separate transitions leading to the first excited state of 7Be ( 7Be 1) from ones leading to the ground state of 7Be( 7Be 0). At incident energies higher than 21 MeV/ A, both zero-degree excitation functions for 7Be 0 and 7Be 1 are well predicted by microscopic distorted-wave Born approximation calculations, but at an incident energy of 14 MeV/ A there are large contributions from complex reaction processes other than the one-step process.