Microscopic particle-rotor model for the low-lying spectrum of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Λ</mml:mi></mml:math>hypernuclei

Abstract

We propose a novel method for low-lying states of hypernuclei based on the particle-rotor model, in which hypernuclear states are constructed by coupling the hyperon to low-lying states of the core nucleus. In contrast to the conventional particle-rotor model, we employ a microscopic approach for the core states; that is, the generator coordinate method (GCM) with the particle number and angular momentum projections. We apply this microscopic particle-rotor model to ${}_{\ensuremath{\Lambda}}^{9}\mathrm{Be}$ as an example employing a point-coupling version of the relativistic mean-field Lagrangian. A reasonable agreement with the experimental data for the low-spin spectrum is achieved using the $\ensuremath{\Lambda}N$ coupling strengths determined to reproduce the binding energy of the $\ensuremath{\Lambda}$ particle.