$NΛ$ interaction from a quark model: $pΛ$ femtoscopy and the hypertriton

Abstract

Understanding the low-energy nucleon--$Λ$ interaction is essential for describing hypernuclear structures, while its spin dependence remains insufficiently constrained by experimental data. In this work, we investigate the $NΛ$ interaction using the quark delocalization color screening model and explore its implications for $pΛ$ femtoscopy and the hypertriton. The energy and scattering phase shifts of the $NΛ$ system are calculated, revealing weak attraction in both the $J^P=0^+$ and $1^+$ channels, but no bound states. The corresponding scattering lengths and effective ranges are found to be $-2.36$ fm and $1.61$ fm for $J^P=0^+$, and $-0.95$ fm and $1.46$ fm for $J^P=1^+$, respectively. Using the Gel'fand--Levitan--Marchenko inverse-scattering method, effective $NΛ$ potentials are reconstructed from the coupled-channel scattering phase shifts and applied to calculate the $pΛ$ femtoscopic correlation function. Comparison with experimental data suggests that the spin-triplet attraction may be underestimated in the present model. Furthermore, employing the Gaussian Expansion Method, we investigate the $NNΛ$ three-body system and obtain a weakly bound hypertriton with a $Λ$ separation energy of $1.06$--$1.16$ MeV. These results demonstrate that $pΛ$ femtoscopic correlations and hypertriton binding provide complementary probes of the spin-dependent $NΛ$ interaction, offering valuable constraints on its low-energy behavior.