6533b872fe1ef96bd12d2e5a

RESEARCH PRODUCT

Neutron halos in the excited states of B12

subject

description

The differential cross sections of the $^{11}\mathrm{B}(d,p)\phantom{\rule{0.16em}{0ex}}^{12}\mathrm{B}$ reaction leading to formation of the ${1}^{+}$ ground state and the 0.95-MeV ${2}^{+}$, 1.67-MeV ${2}^{\ensuremath{-}}$, 2.62-MeV ${1}^{\ensuremath{-}}$, 2.72-MeV ${0}^{+}$, and 3.39-MeV ${3}^{\ensuremath{-}}$ excited states of $^{12}\mathrm{B}$ are measured at ${E}_{d}$ = 21.5 MeV. The analysis of the data is carried out within the coupled-reaction-channels method for the direct neutron transfer and the Hauser-Feshbach formalism of the statistical compound-nucleus model. The spectroscopic factors, asymptotic normalization coefficients, and rms radii of the last neutron in all states studied are deduced. The existence of the neutron halos in the 1.67-MeV ${2}^{\ensuremath{-}}$ and 2.62-MeV ${1}^{\ensuremath{-}}$ states is found, consistent with the earlier published data. New information about the enlarged rms radii of the last neutron in the 2.72-MeV ${0}^{+}$ (5.7 fm) and the unbound 3.389-MeV ${3}^{\ensuremath{-}}$ (5.9 fm) states of $^{12}\mathrm{B}$ was obtained, resulting in the possible existence of neutron halo-like states in $^{12}\mathrm{B}$.