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 E_d = 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.