Search for the missing d -wave neutron excitation states in B 13

A B13(d,d′) inelastic scattering experiment was carried out using a 23 MeV/nucleon B13 beam in order to search for the missing positive parity state with a configuration of Bg.s.12⊗ - d5/2 in the N=8 neutron-rich nucleus B13, referred to as the d-wave neutron excitation state. Several states at excitation energies of 3.6(1), 4.2(1), 5.4(2), and 6.5(2) MeV in B13 were observed in its excitation energy spectra, which were derived from the energies and angles of the scattered deuterons from B13 using the missing mass method. To determine the parity of each populated state, the inelastic scattering differential cross sections (DCSs) were compared to the distorted wave Born approximation (DWBA) calculations. The 5.4- and 6.5-MeV states were inferred to be positive parity states and considered as potential candidates for the missing d-wave neutron excitation state. The gap between s and d shells in B13 and the systematic behavior of neutron-rich Boron isotopes were also investigated based on the experimental findings.