Hyperon–nucleon interaction within chiral effective field theory revisited

Abstract

The ΛN and ΣN interactions are considered at next-to-leading order in SU(3) chiral effective field theory. Different options for the low-energy constants that determine the strength of the contact interactions are explored. Two variants are analysed in detail which yield equivalent results for ΛN and ΣN scattering observables but differ in the strength of the ΛN → ΣN transition potential. The influence of this difference on predictions for light hypernuclei and on the properties of the Λ and Σ hyperons in nuclear matter is investigated and discussed. The effect of the variation in the potential strength of the ΛN -ΣN coupling (also called Λ − Σ conversion) is found to be moderate for the considered 3 Λ H and 4 Λ He hypernuclei but sizable in case of the matter properties. Further, the size of three-body forces and their relation to different approaches to hypernuclear interactions is discussed.PACS. 12.39.Fe Chiral Lagrangians -13.75.Ev Hyperon-nucleon interactions -21.30.Fe Forces in hadronic systems and effective interactions

Strangeness in nuclei and neutron stars

“…[223] and NLO19 of Ref. [220] yield equivalent results for ΛN and ΣN scattering observables, as seen in the left and middle panels of Fig. 33.…”

“…More recently, the NLO13 potential for the ΛN and ΣN systems has been revisited in [220], by exploring a new option for the low-energy constants that determine the strength of the contact inter- actions, so giving rise to the NLO19 version. The NLO19 is constructed trying to reduce the number of low-energy constants needed in the fit to the ΛN and ΣN data, by inferring some of them from the N N sector using SU(3) symmetry.…”

“…Whereas most of the microscopic calculations on hypernuclear structure have been done using Y N meson-exchange models, in the recent years there has been some progress in the study of light hypernuclei with Y N derived from χEFT (see [220,295,296] for recent calculations and references therein). In particular, in Ref.…”

“…As discussed in Sec. 4.2, it has been found that the NLO13 and NLO19 variants yield equivalent results for ΛN and ΣN scattering observables [220]. However, the in-medium Λ and Σ properties in matter are different when using NLO13 or NLO19, as the strength of ΛN -ΣN transition potential changes.…”

A Guided Tour of ab initio Nuclear Many-Body Theory

“…Strong interaction physics is a multi-scale problem, and there are good reasons for making better use of the hierarchy of Effective (Field) Theories at our disposal. At the top level, we have QCD, followed by EFTs involving hyperons that can be eliminated progressively until we arrive at the "traditional" pionful and pionless chiral EFTs (see references [296,297] and references therein). At even lower scales, one can formulate an EFT for nuclear halos (or clusters) [297] and make the connection to nuclear DFT and collective models, which can be understood as EFTs as well [298][299][300][301][302][303][304][305].…”