Λ hypernuclei and their deeply bound states

A Λ hyperon is a good probe to investigate nuclear interior. It can form deeply bound states which have narrow widths, because it is free from Pauli blocking by nucleons and the Λ-nucleon interaction is relatively weak. Taking advantage of the (π+,K+) reaction and utilizing a large superconducting kaon spectrometer (INS-SKS) at KEK 12 GeV PS, deeply bound states of heavy Λ hypernuclei have been studied up to 208LambdaPb. The binding energies of a Λ hyperon were derived even for the sLambda orbital for the first time. It has been shown that the hypernuclear mass dependence of the binding energies is, to the first order, accounted for as a Λ hyperon moving in a Woods-Saxon potential. (orig.)