Neutron skin of 27Al with Skyrme and Korea-IBS-Daegu-SKKU density functionals.

Recent measurement of the parity-violating (PV) asymmetry in the elastic electron scattering on 2 7 Al target evokes the interest in the distribution of the neutron in the nucleus. In this work, we calculate the neutron skin thickness ( R n p ) of 2 7 Al with nonrelativistic nuclear structure models. We focus on the role of the effective mass, symmetry energy and pairing force. Models are selected to have effective masses in the range (0.58–1.05) M where M is the nucleon mass in free space, and stiffness of the symmetry energy is varied by choosing the slope of the symmetry energy in the range 9.4–100.5 MeV. Effect of pairing force is investigated by calculating nuclear properties with and without pairing. With constant force pairing, we obtain R n p = 0. 0 0 1 –0.013 fm. The result is independent of the effective mass and symmetry energy. However, R n p is negative when the pairing force is switched off, so the pairing force plays an essential role to make R n p positive and constrained in a narrow range. We also calculate the PV asymmetry ( A pv ) in the elastic electron- 2 7 Al scattering in the Born approximation at the kinematics of the Qweak experiment. We obtain a very narrow-ranged result A pv = (2. 0 7 − 2. 0 9) × 1 0 − 6 . The result is consistent with the experiment and insensitive to the effective mass and symmetry energy. [ABSTRACT FROM AUTHOR]