Light neutron-rich hypernuclei from the importance-truncated no-core shell model

Wirth, R.; Roth, Robert

doi:10.1016/j.physletb.2018.02.021

Cited by 41 publications

(42 citation statements)

References 62 publications

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“…[1] and in the present work, such 3BFs arise first at next-to-next-to-leading order (N 2 LO) in the chiral expansion [3,81]. For the specific case of the Λ-Σ conversion, the necessity for 3BFs is illustrated in a pedagogical way by the similarity renormalization group (SRG) transformation, a tool that is nowadays commonly applied in studies of few-nucleon systems but also of hypernuclei [53,[82][83][84][85][86]. It amounts to a prediagonalization of the Hamiltonian in momentum space in order to improve the convergence of calculations using various many-body methods.…”

Section: Discussionmentioning

confidence: 99%

Hyperon–nucleon interaction within chiral effective field theory revisited

2020

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The ΛN and ΣN interactions are considered at next-to-leading order in SU(3) chiral effective field theory. Different options for the low-energy constants that determine the strength of the contact interactions are explored. Two variants are analysed in detail which yield equivalent results for ΛN and ΣN scattering observables but differ in the strength of the ΛN → ΣN transition potential. The influence of this difference on predictions for light hypernuclei and on the properties of the Λ and Σ hyperons in nuclear matter is investigated and discussed. The effect of the variation in the potential strength of the ΛN -ΣN coupling (also called Λ − Σ conversion) is found to be moderate for the considered 3 Λ H and 4 Λ He hypernuclei but sizable in case of the matter properties. Further, the size of three-body forces and their relation to different approaches to hypernuclear interactions is discussed.PACS. 12.39.Fe Chiral Lagrangians -13.75.Ev Hyperon-nucleon interactions -21.30.Fe Forces in hadronic systems and effective interactions

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Section: Discussionmentioning

confidence: 99%

Hyperon–nucleon interaction within chiral effective field theory revisited

2020

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“…With this framework, we are also able to address interesting physics questions in the p shell, e.g., whether the attraction provided by the hyperon can shift the neutron drip line [67]. The high precision of the J-NCSM can be used, e.g., to study the charge-symmetry breaking in the A = 4 system [68].…”

Section: Discussionmentioning

confidence: 99%

Hypernuclear no-core shell model

et al. 2018

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We extend the No-Core Shell Model (NCSM) methodology to incorporate strangeness degrees of freedom and apply it to single-Λ hypernuclei. After discussing the transformation of the hyperon-nucleon (YN) interaction into Harmonic-Oscillator (HO) basis and the Similarity Renormalization Group transformation applied to it to improve model-space convergence, we present two complementary formulations of the NCSM, one that uses relative Jacobi coordinates and symmetry-adapted basis states to fully exploit the symmetries of the hypernuclear Hamiltonian, and one working in a Slater determinant basis of HO states where antisymmetrization and computation of matrix elements is simple and to which an importance-truncation scheme can be applied. For the Jacobi-coordinate formulation, we give an iterative procedure for the construction of the antisymmetric basis for arbitrary particle number and present the formulae used to embed two-and three-baryon interactions into the many-body space. For the Slater-determinant formulation, we discuss the conversion of the YN interaction matrix elements from relative to single-particle coordinates, the importance-truncation scheme that tailors the model space to the description of the low-lying spectrum, and the role of the redundant center-of-mass degrees of freedom. We conclude with a validation of both formulations in the four-body system, giving converged ground-state energies for a chiral Hamiltonian, and present a short survey of the A ≤ 7 hyper-helium isotopes. PACS numbers: 21.80.+a, 21.10.Dr, 21.60.De, 05.10.CcStrangeness impacts many fields of physics from heavy-ion collisions to nuclear and neutron star structure. Of particular interest are hypernuclei, which can be produced and studied in the laboratory. Hypernuclei are many-body systems consisting of nucleons and hyperons, baryons that carry strangeness, like the Λ 0 , Σ 0,± , or the Ξ 0,− . These hyperons are distinguishable from the nucleons and can be used as probes for the interior structure of the nucleonic core. Furthermore, hypernuclei extend the isospin SU(2), which is a good approximate symmetry in nuclei, to flavor SU(3) that is broken by the significant mass difference between the strange and the up and down quarks [1]. This breaking allows new types of baryonbaryon interactions such as antisymmetric spin-orbit forces, which are forbidden by isospin symmetry [2].A variety of experiments were performed to study properties of hypernuclei. From the early emulsion experiments (see, e.g., Ref.[3]) to modern accelerator-based experiments, a lot of effort went into the measurement of not only ground-state properties [4][5][6][7][8][9], but also the determination of hypernuclear spectra by gamma-ray spectroscopy [10][11][12][13][14]. Even transition strengths are experimentally accessible [15]. This effort was complemented by various theory developments, e.g., Skyrmeand Brueckner-Hartree-Fock models [16][17][18], the shell model [19][20][21][22][23][24], cluster models [25][26][27][28], and few-body methods [29][30][31][32][3...

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“…It is also pointed out that the ΛN -ΣN coupling contributes to excitation energies [67][68][69]. Recently, the ΛN interactions derived from chiral effective field theory have been developed and are used in several hypernuclear structure calculations such as the no-core shell model calculations [70,71]. For example, in Ref.…”

Section: Comparison Of the Excitation Spectra With The Experimentamentioning

confidence: 99%

Low-lying level structure of Λ hypernuclei and spin dependence of the ΛN interaction with antisymmetrized molecular dynamics

2020

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ΛN spin-spin and spin-orbit splittings in low-lying excitation spectra are investigated for p-shell Λ hypernuclei on the basis of the microscopic structure calculation within the antisymmetrized molecular dynamics, where the ΛN G-matrix interaction derived from the baryon-baryon interaction model ESC (extended soft core) is used. It is found that the ground-state spin-parity is systematically reproduced in the p-shell Λ hypernuclei by tuning the ΛN spin-spin and spin-orbit interactions so as to reproduce the experimental data of 4 Λ H, 7 Λ Li and 9 Λ Be. Furthermore, we also focus on the excitation energies of the excited doublets as well as the energy shifts of them by the addition of a Λ particle.

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Light neutron-rich hypernuclei from the importance-truncated no-core shell model

Cited by 41 publications

References 62 publications

Hyperon–nucleon interaction within chiral effective field theory revisited

Hyperon–nucleon interaction within chiral effective field theory revisited

Hypernuclear no-core shell model

Low-lying level structure of Λ hypernuclei and spin dependence of the ΛN interaction with antisymmetrized molecular dynamics

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