Λ hypernuclear potentials beyond linear density dependence

Abstract

In a recent paper [PLB 837 (2023) 137669] we showed that all measured (1sΛ, 1pΛ) pairs of Λ binding energies in Λ-hypernuclei across the periodic table, 12≤A≤208, can be obtained from a Λ-nucleus optical potential with only two adjustable ΛN and ΛNN parameters, associated with leading linear and quadratic terms in the nuclear density, derived by fitting Λ16N binding energies. Here we extend the previous analysis by performing least-squares fits to the full set of data points. Consequences of suppressing ΛNN interactions between ‘core’ nucleons and ‘excess’ neutrons are studied and related predictions are made for (1sΛ, 1pΛ) binding energies in Λ40,48K, obtainable from upcoming 40,48Ca(e,e′K+) JLab experiments. We find Λ-nucleus partial potential depths of DΛ(2)=−38.6±0.8 MeV (ΛN) and DΛ(3)=11.3±1.4 MeV (ΛNN), with a total depth DΛ=−27.3±0.6 MeV at nuclear-matter density ρ0=0.17 fm−3, consistently with our previous results. Extrapolation to higher nuclear densities and possible relevance to the ‘hyperon puzzle’ in neutron-star matter are discussed.