Large Lorentz scalar and vector potentials in nuclei

Furnstahl, R. J.; Serot, Brian D.

doi:10.1016/s0375-9474(00)00146-9

Cited by 53 publications

(57 citation statements)

References 73 publications

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“…[1,3,4], the effective hadronic Lagrangians of QHD and related models are consistent with the symmetries of QCD: Lorentz invariance, parity invariance, electromagnetic gauge invariance, isospin and chiral symmetry. However, QHD calculations do not include pions explicitly.…”

Section: Introductionmentioning

confidence: 87%

“…In relativistic mean-field models, these become functionals of the ground-state scalar density and of the baryon current. The scalar and vector self-energies play the role of local relativistic Kohn-Sham potentials [1,3]. The mean-field models approximate the exact energy functional, which includes all higher-order correlations, with powers and gradients of densities, with the truncation determined by power counting [3].…”

Section: Comparison With the Dirac-brueckner G Matrixmentioning

confidence: 99%

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Relativistic nuclear model with point-couplings constrained by QCD and chiral symmetry

et al. 2004

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We derive a microscopic relativistic point-coupling model of nuclear many-body dynamics constrained by in-medium QCD sum rules and chiral symmetry. The effective Lagrangian is characterized by density dependent coupling strengths, determined by chiral one-and two-pion exchange and by QCD sum rule constraints for the large isoscalar nucleon self-energies that arise through changes of the quark condensate and the quark density at finite baryon density. This approach is tested in the analysis of the equations of state for symmetric and asymmetric nuclear matter, and of bulk and single-nucleon properties of finite nuclei. In comparison with purely phenomenological mean-field approaches, the built-in QCD constraints and the explicit treatment of pion exchange restrict the freedom in adjusting parameters and functional forms of density dependent couplings. It is shown that chiral (two-pion exchange) fluctuations play a prominent role for nuclear binding and saturation, whereas strong scalar and vector fields of about equal magnitude and opposite sign, induced by changes of the QCD vacuum in the presence of baryonic matter, generate the large effective spin-orbit potential in finite nuclei.

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Section: Introductionmentioning

confidence: 87%

Section: Comparison With the Dirac-brueckner G Matrixmentioning

confidence: 99%

Relativistic nuclear model with point-couplings constrained by QCD and chiral symmetry

et al. 2004

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“…Under this condition, the pseudospin symmetry was identified as a SU(2) symmetry of the Dirac Hamiltonian [7]. In RMF models, nuclear saturation is explained by a cancellation between a large scalar (S) and a large vector (V ) fields [8]. Typical values for these fields in heavy nuclei are of the order of a few hundred MeV (with opposite signs), their sum providing a binding potential of about 60 MeV at the nucleus center.…”

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confidence: 99%

Isospin Asymmetry in the Pseudospin Dynamical Symmetry

et al. 2001

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Pseudospin symmetry in nuclei is investigated considering the Dirac equation with a Lorentz structured Woods-Saxon potential. The isospin correlation of the energy splittings of pseudospin partners with the nuclear potential parameters is studied. We show that, in an isotopic chain, the pseudospin symmetry is better realized for neutrons than for protons. This behavior comes from balance effects among the central nuclear potential parameters. In general, we found an isospin asymmetry of the nuclear pseudospin interaction, opposed to the nuclear spin-orbit interaction which is quasi isospin symmetric.PACS numbers: 21.10. Hw, 21.30.Fe, 21.60.Cs In some heavy nuclei a quasi-degeneracy is observed between single-nucleon states with quantum numbers (n, ℓ, j = ℓ + 1/2) and (n − 1, ℓ + 2, j = ℓ + 3/2) where n, ℓ, and j are the radial, the orbital, and the total angular momentum quantum numbers, respectively. This doublet structure is better expressed using a "pseudo" orbital angular momentum quantum number,l = ℓ + 1, and a "pseudo" spin quantum number,s = 1/2. For example, for [ns 1/2 , (n − 1)d 3/2 ] one hasl = 1, for [np 3/2 , (n − 1)f 5/2 ] one hasl = 2, etc. Exact pseudospin symmetry means degeneracy of doublets whose angular momentum quantum numbers are j =l ±s. This symmetry in nuclei was first reported about 30 years ago [1], but only recently has its origin become a topic of intense theoretical research.In recent papers [2,3,4,5,6] possible underlying mechanisms to generate such symmetry have been discussed. We briefly review the main points of these studies.Blokhin et al.[2] performed a helicity unitary transformation in a nonrelativistic single-particle Hamiltonian. They showed that the transformed radial wave functions have a different asymptotic behavior, implying that the helicity transformed mean field acquires a more diffuse surface. Application of the helicity operator to the nonrelativistic single-particle wave function maps the normal state (l, s) onto the "pseudo" state (l,s), while keeping all other global symmetries [2]. The same kind of unitary transformation was also considered earlier by Bahri et al.[3] to discuss the pseudospin symmetry in the nonrelativistic harmonic oscillator. They showed that a particular condition between the coefficients of spin-orbit and orbit-orbit terms, required to have a pseudospin symmetry in that non-relativistic single particle Hamiltonian, was consistent with relativistic mean-field (RMF) estimates.Ginocchio [4], for the first time, identified the pseudospin symmetry as a symmetry of the Dirac Hamiltonian. He pointed out that the pseudo-orbital angular momentum is just the orbital angular momentum of the lower component of the Dirac spinor. Thus, the pseudospin symmetry started to be regarded and understood in a relativistic way. He also showed that the pseudospin symmetry would be exact if the attractive scalar, S, and the repulsive vector, V , components of a Lorentz structured potential were equal in magnitude: S + V = 0. Under this condition, the pseudospi...

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“…They found that, to accurately reproduce the empirical splittings, one requires a value of m * N /M N between 0.58 and 0.64 at saturation density. Finally, the slope of the energy dependence of the real part of the nucleon-nucleus optical potential, which in a relativistic mean-field approximation is U 0 /M N , has been extracted [20,21,22] from experimental data [23] and has been found to be equal to 0.30 in Ref. [20,21] and 0.35 in Ref.…”

Section: Hadronic Constraints and Observablesmentioning

confidence: 99%

“…Finally, the slope of the energy dependence of the real part of the nucleon-nucleus optical potential, which in a relativistic mean-field approximation is U 0 /M N , has been extracted [20,21,22] from experimental data [23] and has been found to be equal to 0.30 in Ref. [20,21] and 0.35 in Ref. [22], up to 100 MeV of incident kinetic energy, at saturation.…”

Section: Hadronic Constraints and Observablesmentioning

confidence: 99%