New investigation of low-lying states in Be-12 via a H-2(B-13, He-3) reaction

We investigate the low-lying positive-parity states in Be-12, which are populated by the( 2)H(B-13, He-3) reaction via l = 1 proton transfer for the first time using a radioactive beam B-13 at 23 MeV/nucleon. Spectroscopic factors and excitation energies of these states are in reasonable agreement with the shell model predictions. Besides two bound states, we observe a resonant state at E-x = 4.8 +/- 0.1 MeV with an intrinsic width of 0.42 +/- 0.28 MeV, which predominately decays via one neutron to the bound states in 11Be. It most likely corresponds to the E-n = 1.24 MeV state observed in the previous one-proton removal reaction. The spin-parity of 2(+) is tentatively assigned to this resonance according to the analysis of its angular distributions as well as the theoretical calculations, including shell model and Gamow coupled-channel approach.