d(5/2) proton hole strength in neutron-rich (43)P: Shell structure and nuclear shapes near N=28

We report on the use of the one-proton knockout reaction from 44 S to determine the location of d 5 / 2 proton strength in neutron-rich 43 P. The results are used to test two shell-model frameworks with different pictures of the evolution of single-proton energies along the N = 28 isotones near the neutron dripline. We observe a concentration of d 5 / 2 proton hole strength near 1 MeV in excitation energy. This result favors the recent shell-model interaction of Utsuno et al. [Eur. Phys. J. Spec. Top. 150 , 187 (2007)] and provides additional evidence for an oblate shape for 42 Si. ispartof: Physical Review C, Nuclear Physics vol:78 issue:1 status: published