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Zhang Z.,Shanghai JiaoTong University | Chen L.-W.,Shanghai JiaoTong University | Chen L.-W.,Accelerator Centre
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We show that the neutron skin thickness δrnp of heavy nuclei is uniquely fixed by the symmetry energy density slope L(ρ) at a subsaturation cross density ρc≈0.11 fm-3 rather than at saturation density ρ0, while the binding energy difference δE between a heavy isotope pair is essentially determined by the magnitude of the symmetry energy Esym(ρ) at the same ρc. Furthermore, we find a value of L(ρc) leads to a negative Esym(ρ0)-L(ρ0) correlation while a value of Esym(ρc) leads to a positive one. Using data on δrnp of Sn isotopes and δE of a number of heavy isotope pairs, we obtain simultaneously Esym(ρc)=26.65±0.20 MeV and L(ρc)=46.0±4.5 MeV at 95% confidence level, whose extrapolation gives Esym(ρ0)=32.3±1.0 MeV and L(ρ0)=45.2±10.0 MeV. The implication of these new constraints on the δrnp of 208Pb and the core-crust transition density in neutron stars is discussed. © 2013 Elsevier B.V.


Hiyama E.,Accelerator Centre
Few-Body Systems | Year: 2012

Recent development in the study of the structure of light Λ and double Λ hypernuclei is reviewed from the view point of few-body problems and interactions between the constituent particles. In the study the present author and collaborators employed Gaussian expansion method for few-body calculations; the method has been applied to many kinds of few-body systems in the fields of nuclear physics and exotic atomic/molecular physics. We reviewed the following subjects studied using the method: (1) Precise three- and four-body calculations of 7 Λ He, 7 Λ Li, 7 Λ Be, 8 Λ Li, 8 Λ Be, 9 Λ Be, 10 Λ Be, 10 Λ B and 13 Λ C provide important information on the spin structure of the underlying ΛN interaction by comparing the calculated results with the recent experimental data by γ-ray hypernuclear spectroscopy. (2) The Λ-Σ coupling effect was investigated in 4 Λ H and 4 Λ He on the basis of the N + N + N + Λ (Σ) four-body model. (3) A systematic study of double-Λ hypernuclei and the ΛΛ interaction, based on the NAGARA event data ( 6 ΛΛ He), was performed within the α + x + Λ + Λ cluster model (x = n, p, d, t, 3He and α) and α + α + n + Λ + Λ cluster model, (4) The Demachi-Yanagi event was interpreted as observation of the 2 + state of 10 ΛΛ Be, (5) The Hida event was interpreted as observation of the ground state of 11 ΛΛ Be. © 2012 Springer-Verlag.


Funaki Y.,Accelerator Centre
Physical Review C - Nuclear Physics | Year: 2015

The excited states in C12 are investigated by using an extended version of the so-called Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave function, where both the 3α condensate and Be8+α cluster asymptotic configurations are included. A new method is also used to resolve spurious continuum coupling with physical states. I focus on the structures of the "Hoyle band" states (02+,22+, and 42+), which were recently observed above the Hoyle state, and of the 03+ and 04+ states, which were also quite recently identified in experiment. Their resonance parameters and decay properties are reasonably reproduced. All these states have dilute density structure of the 3α or Be8+α clusters with larger root mean square radii than that of the Hoyle state. The Hoyle band is not simply considered to be the Be8(0+)+α rotation as suggested by previous cluster model calculations, nor to be a rotation of a rigid-body triangle-shaped object composed of the 3α particles. This is mainly due to the specificity of the Hoyle state, which has the 3α condensate structure and gives rise to the 03+ state with a prominent Be8(0+)+α structure as a result of very strong monopole excitation from the Hoyle state. © 2015 American Physical Society. ©2015 American Physical Society.


Yoshida K.,Accelerator Centre
Physical Review C - Nuclear Physics | Year: 2010

We investigate the roles of deformation on the giant monopole resonance (GMR), particularly the mixing of the giant quadrupole resonance (GQR) and the effects of the neutron excess in the well-deformed nuclei around Zr110 and in the drip-line nuclei around Zr140 by means of the deformed quasiparticle-random- phase approximation employing the Skyrme and the local-pairing energy-density functionals. It is found that the isoscalar (IS) GMR has a two-peak structure, the lower peak of which is associated with the mixing between the ISGMR and the Kπ=0+ component of the ISGQR. The transition strength of the lower peak of the ISGMR grows as the neutron number increases. In the drip-line nuclei, the neutron excitation is dominant over the proton excitation. We find that for an isovector (IV) excitation the GMR has a four-peak structure due to the mixing of the IS and IV modes as well as the mixing of the Kπ=0 + component of the IVGQR. In addition to the GMR, we find that the threshold strength is generated by neutrons only. © 2010 The American Physical Society.


Chen L.-W.,Shanghai JiaoTong University | Chen L.-W.,Accelerator Centre
Physical Review C - Nuclear Physics | Year: 2011

Within the Skyrme-Hartree-Fock (SHF) approach, we show that for a fixed mass number A, both the symmetry energy coefficient asym(A) in the semiempirical mass formula and the nuclear matter symmetry energy E sym(ρA) at a subsaturation reference density ρA can be determined essentially by the symmetry energy E sym(ρ0) and its density slope L at saturation density ρ0. Meanwhile, we find the dependence of asym(A) on Esym(ρ0) or L is approximately linear and very similar to the corresponding linear dependence displayed by Esym(ρ A), providing an explanation for the relation Esym(ρ A)ρasym(A). Our results indicate that a value of Esym(ρA) leads to a linear correlation between E sym(ρ0) and L and thus can put important constraints on Esym(ρ0) and L. Particularly, the values of E sym(ρ0)=30.5±3 MeV and L= 52.5±20 MeV are simultaneously obtained by combining the constraints from recently extracted Esym(ρA=0.1 fm-3) with those from recent analyses of neutron skin thickness of Sn isotopes in the same SHF approach. © 2011 American Physical Society.

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