Application of Gaussian expansion method to nuclear mean-field calculations with deformation

We analyze recently measured total reaction cross sections for [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Mg isotopes incident on 12 C targets at 240 MeV/nucleon by using the folding model and antisymmetrized molecular dynamics (AMD). The folding model well reproduces the measured reaction cross sections, when the projectile densities are evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation. Matter radii of [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Mg are then deduced from the measured reaction cross sections by fine tuning the parameters of the def-WS model. The deduced matter radii are largely enhanced by nuclear deformation. Fully microscopic AMD calculations with no free parameter well reproduce the deduced matter radii for [24][25][26][27][28][29][30][31][32][33][34][35][36] Mg, but still considerably underestimate them for 37,38 Mg. The large matter radii suggest that 37,38 Mg are candidates for deformed halo nucleus. AMD also reproduces other existing measured ground-state properties (spin parity, total binding energy, and one-neutron separation energy) of Mg isotopes. Neutron-number (N ) dependence of deformation parameter is predicted by AMD. Large deformation is seen from 31 Mg with N = 19 to a drip-line nucleus 40 Mg with N = 28, indicating that both the N = 20 and 28 magicities disappear. N dependence of neutron skin thickness is also predicted by AMD.

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“…In actual sph-GHF and sph-GHFB calculations, we adopt the Gaussian expansion method [46], which reduces numerical tasks.…”

Section: Spherical Hf and Hfbmentioning

confidence: 99%

Ground-state properties of neutron-rich Mg isotopes

et al. 2014

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“…The HF and HFB calculations are implemented in finite nuclei by using the Gaussian expansion method [11][12][13][14] and adopting the Hamiltonian H = H N + V C − H c.m. , where H N , V C and H c.m.…”

Section: Application To Finite Nucleimentioning

confidence: 99%

Erratum: Modified parameter sets of M3Y-type semi-realistic nucleon-nucleon interactions for nuclear structure studies [Phys. Rev. C81, 027301 (2010)]

Nakada¹

2010

Phys. Rev. C

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New parameter-sets of the M3Y-type semi-realistic nucleon-nucleon interaction are obtained, by taking into account the whole contribution of the interaction to the pairing. The interactions are applicable to nuclear structure studies via mean-field calculations and their extensions. Implementing self-consistent mean-field calculations for the spherical nuclei, we confirm that the results do not change significantly from the previous ones, in which the parameters were determined by partly discarding influence of the density-dependent repulsion on the pairing.

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mentioning

confidence: 99%

“…Mean-field models based on the Hartree-Fock (HF) or Hartree-Fock-Bogoliubov (HFB) approximations have been developed by several groups [10][11][12] for the neutron-rich Mg isotopes. Using a Skyrme force in the mean field, Terasaki et al [10] predict 36,38,40 Mg to be strongly deformed with varying deformations for the protons and neutrons.…”

mentioning

confidence: 99%

“…Using a Skyrme force in the mean field, Terasaki et al [10] predict 36,38,40 Mg to be strongly deformed with varying deformations for the protons and neutrons. A Gaussian expansion method [12] with Gogny interaction suggests an extended neutron density tail in 40 Mg. In calculations beyond a mean field [13], an interesting transition is observed from [28][29][30][31][32] Mg showing shape coexistence to 34 Mg with prolate deformation in the ground state.…”

mentioning

confidence: 99%

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Matter radii of32−35Mg

Kanungo¹,

Procházka²,

Horiuchi³

et al. 2011

Phys. Rev. C

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The interaction cross sections of [32][33][34][35] Mg at 900A MeV have been measurmed using the fragment separator at GSI. The deviation from the r 0 A 1/3 trend is slightly larger for 35 Mg, signaling the possible formation of a longer tail in the neutron distribution for 35 Mg. The radii extracted from a Glauber model analysis with Fermi densities are consistent with models predicting the development of neutron skins. The shell structure of nuclei has formed a fundamental basis for understanding their properties. As nuclei accumulate a large excess of neutrons, the conventional shell structure starts to show signs of mutation. Investigations of ground-state properties of neutron-rich nuclei are a key toward the search for the effects leading to the breakdown of the conventional shell structure. The matter radii of neutron-rich nuclei are one of the fundamental properties that constrain nuclear wave functions and carry crucial information on deformation, shell effects, and formation of neutron skins and halos [1].In this Rapid Communication we report on the first determination of the matter radii of [33][34][35] Mg in the N = 20 island of inversion from a measurement of the interaction cross section. The results are consistent with development of neutron skins with 35 Mg showing the possibility of a longer density tail.The breakdown of the N = 20 shell gap was observed through the low excitation energy of the 2 + state in 32 Mg [2]. Much effort has been devoted since then to the study of level schemes in attempting to understand this. The large B(E2) values deduced from the Coulomb excitation * ritu@triumf.ca measurements [3,4] were suggestive of 32 Mg being a deformed nucleus. It should be noted here that the extraction of the deformation value (β) in [3] is obtained under the assumption of a collective model. For a proper understanding of deformation in these nuclei, measured radii are important.The level scheme of 32 Mg from β delayed γ spectroscopy of 32 Na [5] suggests that 32 Mg is not an axially symmetric rotor. It is not a vibrational nucleus either. It was in fact discussed [6], based on a Skyrme-Hartree-Fock description, that this nucleus probably exhibits γ unstable deformation. A relativistic mean-field (RMF) calculation with three-dimensional angular momentum projection involving triaxial degrees of freedom [7] gives a ground state having β = 0.6 and γ = 10 • . Density and radii from such models would be useful for comparison with the present data. Recently, a shape coexistent 0 + state has been found in 32 Mg [8].The Monte Carlo shell model (MCSM) [9] has been considered to be fairly well suited to describe the levels in nuclei around the island of inversion. The predicted level scheme of 32 Mg also does not show features of an axially symmetric rotor.Mean-field models based on the Hartree-Fock (HF) or Hartree-Fock-Bogoliubov (HFB) approximations have been developed by several groups [10][11][12] for the neutron-rich 021302-1 0556-2813/2011/83(2)/021302(4)

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Application of Gaussian expansion method to nuclear mean-field calculations with deformation

Cited by 44 publications

References 20 publications

Ground-state properties of neutron-rich Mg isotopes

Ground-state properties of neutron-rich Mg isotopes

Erratum: Modified parameter sets of M3Y-type semi-realistic nucleon-nucleon interactions for nuclear structure studies [Phys. Rev. C81, 027301 (2010)]

Matter radii of32−35Mg

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