Evolution of the $E(1/2^+_1)-E(3/2^+_1)$ energy spacing in odd-mass K,   Cl and P isotopes for $N=20-28$
  The energy of the first excited state in the neutron-rich N=28 nucleus 45Cl has been established via in-beam gamma-ray spectroscopy following proton removal. This energy value completes the systematics of the E(1/2^+_1)-E(3/2^+_1) level spacing in odd-mass K, Cl and P isotopes for N=20-28. The results are discussed in the framework of shell-model calculations in the sd-fp model space. The contribution of the central, spin-orbit and tensor components is discussed from a calculation based on a proton single-hole spectrum from G-matrix and pi + rho meson exchange potentials. A composite model for the proton 0d_{3/2}-1s_{1/2} single-particle energy shift is presented. 
A. Gade, B.A. Brown, D. Bazin, C.M. Campbell, J.A. Church, D.-C.   Dinca, J. Enders, T. Glasmacher, M. Horoi, Z. Hu, K. W. K...