A semi-empirical formula for the energy spacings in Λ-hypernuclear excitation spectra

A semi-empirical formula is presented which gives a semi-quantitative account of the excitation energies in Λ-hypernuclear excitation spectra. Many elaborate studies made were numerical, but our studies yield an analytical expression. Different three-dimensional harmonic oscillators for the Λ and the neutron-hole reproduce the observed energy spacings fairly well. However, it would be misleading that the oscillators give the wave functions of the corresponding states also. In the light of harmonic excitations, we briefly discuss some phenomenological and microscopic Λ-hypernuclear calculations. (author). 19 refs., 1 tab