Nuclear Structure and Magnetic Moment of the Unstable 12B-12N Mirror Pair

Magnetic moments of the A=12 unstable mirror pair nuclides ¹²B and ¹²N have been measured by the β-NMR technique. The experimentally measured magnetic moments are μ(¹²B)=1.001(17)μ_N and μ(¹²N)=0.4571(1)μ_N. The improved shell model using an SFO Hamiltonian with enhanced spin-isospin monopole proton-neutron interaction and modified single-particle energies is employed to calculate the magnetic moments of ¹²B and ¹²N. The calculation yields μ (¹²B)=0.929μ_N and μ(¹²N)=0.452μ_N and has produced a new magic number 6 for the short-lived unstable mirror pair nuclides ¹²B and ¹²N.