Collective excitations of $\Lambda$ hypernuclei

Abstract

We discuss low-lying collective excitations of $\Lambda$ hypernuclei using the self-consistent mean-field approaches. We first discuss the deformation properties of $\Lambda$ hypernuclei in the $sd$-shell region. Based on the relativistic mean-field (RMF) approach, we show that the oblate deformation for ${}^{28}$Si nucleus may disappear when a $\Lambda$ particle is added to this nucleus. We then discuss the rotational excitations of ${}_{\Lambda }^{25}$Mg nucleus using the three-dimensional potential energy surface in the deformation plane obtained with the Skyrme-Hartree-Fock method. The deformation of ${}_{\Lambda }^{25}$Mg nucleus is predicted to be slightly reduced due to an addition of $\Lambda$ particle. We demonstrate that this leads to a reduction of electromagnetic transition probability, $B(E2)$, in the ground state rotational band. We also present an application of random phase approximation (RPA) to hypernuclei, and show that a new dipole mode, which we call a soft dipole $\Lambda$ mode, appears in hypernuclei, which can be interpreted as an oscillation of $\Lambda$ particle against the core nucleus.

8 pages, 5 figures. A talk given at XI International Conference on Hypernuclear and Strange Particle Physics (HYP2012), Oct. 1-5, 2012, Barcelona, Spain

References in corpus (11)

• Beyond the relativistic mean-field approximation (III): collective Hamiltonian in five dimensions
• Configuration mixing of angular-momentum and particle-number projected triaxial HFB states using the Skyrme energy density functional
• Deformation of Lambda hypernuclei
• Deformation of hypernuclei studied with antisymmetirzed molecular dynamics
• Shape of Lambda hypernuclei in (beta,gamma) deformation plane
• Dipole responses in Nd and Sm isotopes with shape transitions
• Description of single-Lambda hypernuclei with relativistic point coupling model
• Di-neutron clustering and deuteron-like tensor correlation in nuclear structure focusing on 11Li
• Modification of triaxial deformation and change of spectrum in ${}_{\Lambda }^{25}$Mg caused by $\Lambda$ hyperon
• Relation between shrinkage effect and compression of rotational spectrum in ${}_{\Lambda }^7$Li hypernucleus
• Application of random phase approximation to vibrational excitations of double-$\Lambda$ hypernuclei

Cited by in corpus (3)

• Triaxially deformed relativistic point-coupling model for $\Lambda$ hypernuclei: a quantitative analysis of hyperon impurity effect on nuclear collective properties
• Production of light hypernuclei with light-ion beams and targets
• Reaction cross sections of hypernuclei and the shrinkage effect