Low-energy hypernuclear spectra with microscopic particle-rotor model with relativistic point coupling hyperon-nucleon interaction

Abstract

We extend the microscopic particle-rotor model for hypernuclear low-lying states by including the derivative and tensor coupling terms in the point-coupling nucleon-$\Lambda$ particle ($N\Lambda$) interaction. Taking ${}_{\Lambda }^{13}$C as an example, we show that a good overall description for excitation spectra is achieved with four sets of effective $N\Lambda$ interaction. We find that the $\Lambda$ hyperon binding energy decreases monotonically with increasing the strengths of the high-order interaction terms. In particular, the tensor coupling term decreases the energy splitting between the first $1/2^{-}$ and $3/2^{-}$ states and increases the energy splitting between the first $3/2^{+}$ and $5/2^{+}$ states in ${}_{\Lambda }^{13}$C.

Comments: 11 pages, 5 figures