Asymptotic normalization coefficients and halo radii of 12B in the excited states

Abstract

We present the results of measurements and analysis of the differential cross sections of the 11B(d, p)12B reaction leading to formation of the 1+ ground state and the 0.953-MeV 2+, 1.674-MeV 2−, 2.621-MeV 1−, 2.723-MeV 0+, 3.389-MeV 3− excited states of 12B at Ed = 21.5 MeV. The analysis of the data was carried out within the coupled-reaction-channels method for the direct neutron transfer and the Hauser-Feshbach formalism of the statistical compound-nucleus model. We deduced the spectroscopic factors, asymptotic normalization coefficients, and rms radii of the last neutron in all states studied. The existence of the neutron halos in the 1.674-MeV 2− and 2.621-MeV 1− states was found in consistence with the earlier published data. New information about the enlarged rms radii (6.5 fm) of the last neutron in the unbound 3.389-MeV 3− states of 12B was obtained, which may indicate the evidence of the neutron halo with the orbital momentum of the last neutron equal to two.