Massive neutron stars and Λ-hypernuclei in relativistic mean field models

Based on relativistic mean field (RMF) models, we study finite Λ-hypernuclei and massive neutron stars. The effective N-N interactions PK1 and TM1 are adopted, while the N-Λ interactions are constrained by reproducing the binding energy of Λ-hyperon at 1s orbit of Λ⁴⁰Ca. It is found that the Λ-meson couplings follow a simple relation, indicating a fixed Λ potential well for symmetric nuclear matter at saturation densities, i.e., around V_Λ = -29.786 MeV. With those interactions, a large mass range of Λ-hypernuclei can be described well. Furthermore, the masses of PSR J1614-2230 and PSR J0348+0432 can be attained adopting the Λ-meson couplings gσΛ/gσN ≳ 0.73,gωΛ/gωN ≳ 0.80 for PK1 and gσΛ/gσN ≳ 0.81, gωΛ/gωN ≳ 0.90 for TM1, respectively. This resolves the hyperon puzzle without introducing any additional degrees of freedom.