Study of 1/2⁺ states in ¹¹B using the ¹⁰Be(d,n)¹¹B reaction

Recent experiments have provided some evidence for a 1/2⁺ level in ¹¹B located just above the proton threshold, with a large l_p=0 spectroscopic factor. Such a level could have important implications for ¹¹Be beta decay and ¹⁰Be+p reaction rates. We have measured angular distributions of the proton transfer reaction ¹⁰Be(d,n)¹¹B in normal kinematics for incident deuteron energies of 4 and 7 MeV. Neutrons were detected using the time-of-flight technique, with experimental conditions optimized to provide an excitation energy resolution of ≈40 keV in the proton threshold region of ∼11 MeV. The angular distributions to specific final states allow the orbital angular momentum of the transferred proton l_p to be identified, while the absolute cross sections provide information about the spectroscopic factors. We see no evidence of a 1/2⁺ level near E_x=11.4 MeV. The deduced excitation energies, spectroscopic factors, and total widths of the observed 1/2⁺ levels will be presented.