Quenching of single-particle strength in A = 15 nuclei.

A simultaneous determination of the occupancy of the 1s and 0d orbitals outside of ¹⁴C and ¹⁴N has been made via the neutron-adding (d,p) reaction in inverse kinematics using the HELIOS spectrometer at Argonne National Laboratory. Spectroscopic factors for these orbitals are found to be about 0.6 that of the single-particle values, indicating a quenching of single-particle motion consistent with a large body of transfer-reaction data. The magnitude of this quenching and its dependence on ΔS, the difference between proton and neutron separation energies, is inconsistent with that seen in intermediate-energy knockout reactions on complex targets.