Abstract.
A recently introduced relativistic nuclear energy density functional, constrained by features of low-energy QCD, is extended to describe the structure of hypernuclei. The density-dependent mean field and the spin-orbit potential of a Λ-hyperon in a nucleus, are consistently calculated using the SU(3) extension of in-medium chiral perturbation theory. The leading long-range ΛN interaction arises from kaon-exchange and 2π-exchange with a Σ-hyperon in the intermediate state. Scalar and vector mean fields, originating from in-medium changes of the quark condensates, produce a sizeable short-range spin-orbit interaction. The model, when applied to oxygen as a test case, provides a natural explanation for the smallness of the effective Λ spin-orbit potential: an almost complete cancellation between the background contributions (scalar and vector) and the long-range terms generated by two-pion exchange.
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Finelli, P. Hypernuclei and in-medium chiral dynamics . Eur. Phys. J. Spec. Top. 156, 183–190 (2008). https://doi.org/10.1140/epjst/e2008-00615-1
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DOI: https://doi.org/10.1140/epjst/e2008-00615-1