Physics Letters B (Feb 2023)
Constraints from Λ hypernuclei on the ΛNN content of the Λ-nucleus potential
Abstract
A depth of DΛ≈−28 MeV for the Λ-nucleus potential was confirmed in 1988 by studying Λ binding energies deduced from (π+,K+) spectra measured across the periodic table. Modern two-body hyperon-nucleon interaction models require additional interaction terms, most likely ΛNN three-body terms, to reproduce DΛ. Here we apply a suitably constructed Λ-nucleus density dependent optical potential to binding energy calculations of observed 1sΛ and 1pΛ states in the mass range 12≤A≤208. The resulting ΛNN contribution to DΛ, about 14 MeV repulsion at symmetric nuclear matter density ρ0=0.17 fm−3, makes DΛ increasingly repulsive at ρ≳3ρ0, leading possibly to little or no Λ hyperon content of neutron-star matter. This suggests in some models a stiff equation of state that may support two solar-mass neutron stars.
