Microscopic particle-rotor model for low-lying spectrum of Lambda hypernuclei

TL;DR

This paper introduces a microscopic particle-rotor model for hypernuclei, coupling hyperons to core states derived from the generator coordinate method, and successfully applies it to $^9_\Lambda$Be with good experimental agreement.

Contribution

It develops a novel microscopic particle-rotor model for hypernuclei using GCM for core states, improving upon conventional models.

Findings

Achieves good agreement with experimental low-spin spectra for $^9_\Lambda$Be.

Uses a relativistic mean-field Lagrangian with $ extLambda N$ coupling strengths.

Demonstrates the effectiveness of the microscopic approach for hypernuclear structure.

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 $^9_\Lambda $Be 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 $\Lambda N$ coupling strengths determined to reproduce the binding energy of the $\Lambda$ particle.