Theoretical evidence for di-molecular rotational behaviour in the hypernuclei ? 8 Li and ? 8 Be

Abstract

We have performed microscopic cluster studies of light Z-hypernuclei based on effective nucleon-nucleon and two different sigma-nucleon interactions. Our calculation confirms a bound 0 + state in 4He and 4H, but reveals no evidence for levels in other partial waves. We have investigated the 8Li and ~Be hypernuclei in a microscopic 3-cluster approach. For both hypernuclei, our calculation shows that the lowest levels in the partial waves J = 0 -4 are bound or quasibound states of collective nature and show a strong c~ § 4H and ~ § 4He clustering. These levels form a sequence of states which can be well interpreted as arising from a rotating ~ + 4H or ~ + 4He di-molecule. Our results are compared to those of similar studies for light A-hypernuclei which do not show evidence for this kind of collective degrees of freedom.