Measurement of the spin and magnetic moment of {sup 23}Al

For the first time, we obtained the g factor for the ground state of {sup 23}Al by use of a {beta}-NMR measurement. {sup 23}Al has a small proton separation energy and is a potential proton-halo candidate. The obtained g factor, vertical bar g vertical bar =1.557{+-}0.088, clearly shows the spin and parity, J{sup {pi}}=5/2{sup +}, for {sup 23}Al, which is the same as that of its mirror partner, {sup 23}Ne. The possible nuclear structure of {sup 23}Al is also discussed.