Abstract
A previously derived relativistic energy density functional for nuclei, based on low-energy in-medium chiral dynamics, is generalized to implement constraints from chiral SU (3) effective field theory and applied to Λ hypernuclei. Density-dependent central and spin-orbit mean fields are calculated for a Λ hyperon using the SU (3) extension of in-medium chiral perturbation theory to two-loop order. Long range ΛN interactions arise from kaon-exchange and from two-pion-exchange with a Σ hyperon in the intermediate state. Short-distance dynamics is encoded in contact interactions. They include scalar and vector mean fields reflecting in-medium changes of quark condensates, constrained by QCD sum rules. The Λ single particle orbitals are computed for a series of hypernuclei from 13ΛC to 208ΛPb. The role of a surface (derivative) term is studied. Its strength is found to be compatible with a corresponding estimate from in-medium chiral perturbation theory. Very good agreement with hypernuclear spectroscopic data is achieved. The smallness of the Λ-nuclear spin-orbit interaction finds a natural explanation in terms of an almost complete cancellation between short-range scalar/vector contributions and longer range terms generated by two-pion exchange.
Original language | English |
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Pages (from-to) | 163-183 |
Number of pages | 21 |
Journal | Nuclear Physics, Section A |
Volume | 831 |
Issue number | 3-4 |
DOIs | |
State | Published - 15 Dec 2009 |
Keywords
- Chiral dynamics
- Hypernuclei
- Nuclear energy density functionals
- QCD sum rules