N¯Nbinding energies

A reported bound state of $\overline{p}n$ at -83 MeV is compared with calculations on the boundary-condition model (BCM) for $\mathrm{NN}$ scattering. The most probable orbital assignment for the bound state appears to be ${}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$ or ${}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$, but it is not possible to distinguish between these two assignments by binding energies alone. At least half a dozen other bound states are predicted. The imaginary part of the core boundary condition is quite small in the present case. Comparison with published calculations using the Bryan-Phillips static (BPS) potential shows that the latter has a somewhat richer spectrum and includes ${}_{}{}^3{}_{}{}^{}D_1^{}{}_{}{}^{}$ as equally probable orbital for the observed state. The BCM and BPS potentials differ substantially in their spin-isospin dependence, but distinguishing data do not now exist.