Abstract
The magnetic moments of and were measured by using spin-polarized radioactive nuclear beams which were obtained from the projectile fragmentation reaction. The observed magnetic moment of , ‖μN)‖=(0.352±0.002), where is the nuclear magneton, falls outside the Schmidt lines. By virtue of a simplifying feature of nuclear structure inherent in a valence nucleus, the deviation from the Schmidt value is attributed on firm ground to admixing of the configurations in which two neutrons in the sd shell are coupled to =. This interpretation is confirmed in standard shell-model calculations. The calculations reproduce fairly well the experimentally inferred amount of admixture, as well as the experimental magnetic moment itself. The magnetic moment for was determined as ‖μB)‖=(2.545±0.020). The result is substantially smaller than the π single-particle value, and the shell-model calculations indicate that the quenching of μ largely stems from = configurations of the sd neutrons. The observed amount of quenching, however, is larger than the shell-model predictions, suggesting an enhanced contribution of the neutron configurations. This result is explained if the pairing energy for neutrons in the sd shell of a neutron-rich nucleus is assumed to diminish by about 30%. We also find that the use of the reduced pairing energy improves agreements in the magnetic moment and low-lying energy levels of as well. © 1996 The American Physical Society.
- Received 28 November 1995
DOI:https://doi.org/10.1103/PhysRevC.53.2142
©1996 American Physical Society