Pseudospin symmetry in resonant states in deformed nuclei

Zhang, Yue; Luo, Yu-Xuan; Liu, Q.; Guo, Jian-You

doi:10.1016/j.physletb.2023.137716

Cited by 7 publications

(3 citation statements)

References 57 publications

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“…由于具有场论基础和可自动给出原子核自旋-轨道劈裂等优势, 相对论平均场理论在原子核性质计算中得到了广泛应用. 近年来, 相对论平均场理论得到了不断完善和发展, 成功地描述了原子核的均方根半径、质量、中子和质子分离能、自旋对称等性质 [51][52][53][54][55][56][57][58][59][60][61][62] . 关于描述超核基态性质的相对论平均场理论可以参考文献 [21][22][23][24][25][26][27], 本文给出简要的介绍.…”

Section: 理论模型unclassified

Isoscalar giant resonances of <inline-formula><tex-math id="M1">\begin{document}$^{{\bf{18}}}_{{\boldsymbol{\Lambda\Lambda}}}{\bf{O}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20231531_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20231531_M1.png"/></alternatives></inline-formula> in relativistic approach

Wen,

Sun,

Cao

et al. 2024

Acta Phys. Sin.

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The interactions between hyperon-nucleon and hyperon-hyperon have been an important topic in strangeness nuclear physics, which play important role in understanding the properties of hypernuclei and equation of state of strangeness nuclear matter. It is very difficult to perform a direct scattering experiment of the nucleon and hyperon because the short lifetime of the hyperon. Therefore, the hyperon-nucleon and hyperon-hyperon interactions have been mainly investigated experimentally by γ spectroscopy of single-Λ or double-Λ hypernuclei. There are also many theoretical methods developed to describe the properties of hypernuclei. These models are focused mostly on the ground state properties of hypernuclei, and have obtained exciting results in producing the banding energies, the energies of single-particle levels, deformation, and other properties of hypernuclei. Only a few work adopting Skyrme energy density functionals is devoted to study the collective excitation properties of hypernuclei. In present work, we have extended the relativistic mean field and relativistic random phase approximation theories to study the collective excitation properties of hypernuclei, and apply the methods to study the isoscalar collective excited state properties of double Λ hypernuclei. First, the effect of Λ hyperons on the single-particle energies of 16O and 18ΛΛO is discussed in the relativistic mean field theory, the calculations are performed within TM1 parameter set and related hyperon-nucleon and hyperon-hyperon interactions. We find that it gives a larger attractive effect on the 1s1/2 states of protons and neutrons, while gives a weaker attractive effect on the states around Fermi surface. The self-consistent relativistic random phase approximation is applied to study the collective excited state properties of hypernucleus 18ΛΛO. The isoscalar giant monopole and quadrupole resonances are calculated and analysed in detail, we pay more attention to the effect of the inclusion of Λ hyperons on the properties of giant resonances. Compared to the strength distributions of 16O, changes on the response functions of 18ΛΛO are evidently found both on the isoscalar giant monopole and quadrupole resonances. It is shown that the difference comes mainly from the changes of Hartree energies of particle-hole configurations and the contributions of the excitations of Λ hyperons. We find that the hyperon-hyperon residual interactions have small effect on the monopole and quadrupole response functions in the low-energy region, and have almost no effect on the response functions in the high-energy region.

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Section: 理论模型unclassified

Isoscalar giant resonances of <inline-formula><tex-math id="M1">\begin{document}$^{{\bf{18}}}_{{\boldsymbol{\Lambda\Lambda}}}{\bf{O}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20231531_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="4-20231531_M1.png"/></alternatives></inline-formula> in relativistic approach

Wen,

Sun,

Cao

et al. 2024

Acta Phys. Sin.

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“…Furthermore, the continuum effects are taken into account automatically, which promises extensive reliability in the description of novel phenomena in unstable nuclei, such as the novel halo phenomena observed in both spherical and deformed nuclei [64][65][66][67][68]. The relativistic scheme has facilitated numerous investigations into the origin of the PSS [44,46,69], the relationship between PSS and spin-orbit effects [70], the PSS's dynamical properties [71][72][73] and non-perturbative nature [74][75][76], the PSS in deformed nuclei [77][78][79][80][81][82][83], the PSS in hypernuclei [84,85], and the resonant states [83,[86][87][88][89][90][91][92][93][94][95][96], etc.…”

Section: Introductionmentioning

confidence: 99%

Pseudo-Spin Symmetry and the Hints for Unstable and Superheavy Nuclei

Geng,

Wang,

Liu

et al. 2024

Symmetry

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The pseudo-spin symmetry (PSS) provides an important angle to understand nuclear microscopic structure and the novel phenomena found in unstable nuclei. The relativistic Hartree–Fock (RHF) theory, that takes the important degrees of freedom associated with the π-meson and ρ-tensor (ρ-T) couplings into account, provides an appropriate description of the PSS restoration in realistic nuclei, particularly for the pseudo-spin (PS) doublets with high angular momenta (l˜). The investigations of the PSS within the RHF theory are recalled in this paper by focusing on the effects of the Fock terms. Aiming at common artificial shell closures appearing in previous relativistic mean-field calculations, the mechanism responsible for the PSS restoration of high-l˜ orbits is stressed, revealing the manifestation of nuclear in-medium effects on the PSS, and thus, providing qualitative guidance on modeling the in-medium balance between nuclear attractions and repulsions. Moreover, the essential role played by the ρ-T coupling, that contributes mainly via the Fock terms, is introduced as combined with the relations between the PSS and various nuclear phenomena, including the shell structure and the evolution, novel halo and bubble-like phenomena, and the superheavy magicity. As the consequences of the nuclear force in complicated nuclear many-body systems, the PSS itself and the mechanism therein can not only deepen our understanding of nuclear microscopic structure and relevant phenomena, but also provide special insight into the nature of the nuclear force, which can further enrich our knowledge of nuclear physics.

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“…In addition to the exploration of origin, there are many studies on the phenomena, properties, and observables that may hold PSS. For example, PSS in spherical nuclei [17][18][19][20][21][22] and deformed nuclei [23][24][25][26][27][28], PSS in scattering states [29][30][31][32], resonant states [33][34][35][36][37], anti-nucleon spectra [38,39], and hyperon spectra [40,41], the pseudospin partner bands in the rotational spectra in 108 Tc [10] and 189 Pt [11], and PSS in the triplet bands in the spin symmetry of Dirac Sea [46], and the supersymmetric properties of PSS [47][48][49] were also investigated. More research on PSS can be found in [50,51] and recent references.…”

Section: Introductionmentioning

confidence: 99%

Exploration of origin and breaking mechanism of pseudospin symmetry in relativistic point-coupling model with similarity renormalization group

Huang,

Guo,

Liu

et al. 2023

Phys. Scr.

Self Cite

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The pseudospin symmetry (PSS) is an important physical concept in atomic nuclei. The relativistic point-coupling model is ﬁrst used to explore the origin and breaking mechanism of PSS in real nuclei with 208Pb as an illustrated example. PSS observed in the single particle spectra of heavy nuclei is reproduced in the present calculation. The inﬂuences of the diﬀerent point-coupling interactions on PSS are investigated, it is found that the four-fermion scalar and vector couplings play a dominate role at PSS. The quality of PSS depends on the competition of four-fermion scalar and vector couplings. Those the PSS is better for the weakly bound levels and the energy splittings are more sensitive to the interaction strengths for the deeply bound levels are well explained in terms of the derivative of Σ potential with r. In combination with the similarity renormalization group, the origin and breaking mechanism of PSS are clariﬁed.

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Pseudospin symmetry in resonant states in deformed nuclei

Cited by 7 publications

References 57 publications

Pseudo-Spin Symmetry and the Hints for Unstable and Superheavy Nuclei

Exploration of origin and breaking mechanism of pseudospin symmetry in relativistic point-coupling model with similarity renormalization group

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