Relativistic RPA for isobaric analogue and Gamow–Teller resonances in closed shell nuclei

Conti, Claudio; Galeão, A. P.; Krmpotić, F.

doi:10.1016/s0370-2693(98)01373-2

Cited by 30 publications

(43 citation statements)

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“…The self-consistent RPA approach was first developed based on the relativistic Hatree (RH) model [54]. The negative-energy states in the Dirac sea are found to be very important to construct the RPA configuration space, which remarkably influence the isoscalar strength distributions [55] and the sum rule of Gamow-Teller (GT) transitions [56].…”

Section: Introductionmentioning

confidence: 99%

Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations

Niu

Liang

et al. 2017

Phys. Rev. C

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The self-consistent quasiparticle random-phase approximation (QRPA) approach is formulated in the canonical single-nucleon basis of the relativistic Hatree-Fock-Bogoliubov (RHFB) theory.This approach is applied to study the isobaric analog states (IAS) and Gamov-Teller resonances (GTR) by taking Sn isotopes as examples. It is found that self-consistent treatment of the particleparticle residual interaction is essential to concentrate the IAS in a single peak for open-shell nuclei and the Coulomb exchange term is very important to predict the IAS energies. For the GTR, the isovector pairing can increase the calculated GTR energy, while the isoscalar pairing has an important influence on the low-lying tail of the GT transition. Furthermore, the QRPA approach is employed to predict nuclear β-decay half-lives. With an isospin-dependent pairing interaction in the isoscalar channel, the RHFB+QRPA approach almost completely reproduces the experimental β-decay half-lives for nuclei up to the Sn isotopes with half-lives smaller than one second. Large discrepancies are found for the Ni, Zn, and Ge isotopes with neutron number smaller than 50, as well as the Sn isotopes with neutron number smaller than 82. The potential reasons for these discrepancies are discussed in detail.

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Section: Introductionmentioning

confidence: 99%

Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations

Niu

Liang

et al. 2017

Phys. Rev. C

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“…Second, to cancel the contact interaction coming from the pseudovector pion-nucleon coupling, a zero-range counter-term is needed with the strength g ′ = 1/3 exactly [15]. However, in order to reproduce the excitation energies of the GTR, g ′ must be treated as an adjustable parameter in RMF+RPA model with the value g ′ ≈ 0.6 [12,14]. In this Letter, for the first time a fully selfconsistent charge-exchange relativistic RPA model is established, based on the relativistic Hartree-Fock (RHF) approach [15,16].…”

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confidence: 99%

Spin-Isospin Resonances: A Self-Consistent Covariant Description

2008

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For the first time a fully self-consistent charge-exchange relativistic RPA based on the relativistic Hartree-Fock (RHF) approach is established. The self-consistency is verified by the so-called isobaric analog state (IAS) check. The excitation properties and the non-energy weighted sum rules of two important charge-exchange excitation modes, the Gamow-Teller resonance (GTR) and the spindipole resonance (SDR), are well reproduced in the doubly magic nuclei 48 Ca, 90 Zr and 208 Pb without readjustment of the particle-hole residual interaction. The dominant contribution of the exchange diagrams is demonstrated.PACS numbers: 24.30. Cz, 21.60.Jz, 24.10.Jv, 25.40.Kv At present, spin-isospin resonances become one of the central topics in nuclear physics and astrophysics. Basically, a systematic pattern of the energy and collectivity of these resonances could provide direct information on the spin and isospin properties of the in-medium nuclear interaction, and the equation of state of asymmetric nuclear matter. Furthermore, a basic and critical quantity in nuclear structure, neutron skin thickness, can be determined indirectly by the sum rule of spin-dipole resonances (SDR) [1,2] or the excitation energy spacing between isobaric analog states (IAS) and Gamow-Teller resonances (GTR) [3]. More generally, spin-isospin resonances allow one to attack other kinds of problems outside the realm of nuclear structure, like the description of neutron star and supernova evolutions, the β-decay of nuclei which lie on the r-process path of stellar nucleosynthesis [4,5], even the existence of exotic odd-odd nuclei [6] and the efficiency of a solar neutrino detector [7].It was realized long ago that the Random Phase Approximation (RPA) is an appropriate microscopic approach for charge-exchange giant resonances [8,9]. The importance of full self-consistency was stressed [9], and Skyrme-RPA calculations of charge-exchange modes exist for about 30 years [10]. Recently, a fully self-consistent charge-exchange Skyrme-QRPA model has been developed [11]. Self-consistency is an extremely important requirement for the analysis of long isotopic chains extending towards the drip lines. On the relativistic side, so far the charge-exchange (Q)RPA model based on the relativistic mean field (RMF) theory has been developed [3,12,13,14].However, the self-consistency of the RMF+RPA is not completely fulfilled for the following reasons. First, the isovector pion plays an important role in the relativistic description of spin-isospin resonances. Because of the parity conservation this degree of freedom is absent in the ground-state description under the Hartree approximation. Therefore, the pion is out of control in this bestfitting effective field theory. Second, to cancel the contact interaction coming from the pseudovector pion-nucleon coupling, a zero-range counter-term is needed with the strength g ′ = 1/3 exactly [15]. However, in order to reproduce the excitation energies of the GTR, g ′ must be treated as an adjustable parameter in RMF+RPA m...

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“…Up to now most investigations in the relativistic approach are restricted to the electric excitations. Although the GT resonance has been recently studied in the relativistic RPA [15,16] a proper relativistic form of the p-h interaction in the spin-isospin channel has not been obtained.…”

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confidence: 99%

“…There are several ways to introduce this term in the interaction Lagrangian [15,18]. However, It has been pointed out in Ref.…”

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confidence: 99%

The Gamow-Teller resonance in finite nuclei in the relativistic random phase approximation

Chen

Giai

et al. 2004

Eur. Phys. J. A

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Gamow-Teller(GT) resonances in finite nuclei are studied in a fully consistent relativistic random phase approximation (RPA) framework. A relativistic form of the Landau-Migdal contact interaction in the spin-isospin channel is adopted. This choice ensures that the GT excitation energy in nuclear matter is correctly reproduced in the non-relativistic limit. The GT response functions of doubly magic nuclei 48 Ca, 90 Zr and 208 Pb are calculated using the parameter set NL3 and g ′ 0 =0.6 . It is found that effects related to Dirac sea states account for a reduction of 6-7% in the GT sum rule. 21.60.Jz, 24.10.Jv, 24.30.Cz In recent years, the relativistic mean field (RMF) theory with non-linear meson selfinteractions has achieved a great success in describing bulk properties of nuclei, not only spherical but also deformed nuclei and nuclei far from the β-stability line [1]. In particular, a fully consistent relativistic random phase approximation (RPA) based on the RMF has been established [2,3,4,5]. The consistency implies that the particle-hole (p-h) residual interaction and the nuclear mean field are calculated from the same effective Lagrangian. The relativistic RPA is equivalent to the time-dependent RMF in the small amplitude limit [6,7] only if the particle-hole configuration space includes not only the pairs formed from the occupied and unoccupied Fermi states but also the pairs formed from the Dirac states and occupied Fermi states [8].It has been found that the effective Lagrangians which can well describe the ground state properties of nuclei could also reproduce their collective excited states and giant resonances [9].The investigation of nuclear excitations involving spin-isospin Gamow-Teller(GT) resonances

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Relativistic RPA for isobaric analogue and Gamow–Teller resonances in closed shell nuclei

Cited by 30 publications

References 31 publications

Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations

Self-consistent relativistic quasiparticle random-phase approximation and its applications to charge-exchange excitations

Spin-Isospin Resonances: A Self-Consistent Covariant Description

The Gamow-Teller resonance in finite nuclei in the relativistic random phase approximation

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