arXiv subjects

Yi-Yuan Cheng

Publications and source records attributed to Yi-Yuan Cheng.

4 recordsLinked to original sources

arXiv2021

Effects of $\bm\la$ hyperons on the deformations of even-even nuclei

The deformations of multi-$\la$ hypernuclei corresponding to even-even core nuclei ranging from $^8$Be to $^{40}$Ca with 2, 4, 6, and 8 hyperons are studied in the framework of the deformed Skyrme-Hartree-Fock approach. It is found that the deformations are reduced when adding 2 or 8 $\la$ hyperons, but enhanced when adding 4 or 6 $\la$ hyperons. These differences are attributed to the fact that $\la$ hyperons are filled gradually into the three deformed $p$ orbits, of which the [110]1/2$^-$ orbit is prolately deformed and the degenerate [101]1/2$^-$ and [101]3/2$^-$ orbits are oblately deformed.

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arXiv2020

Study of $Ξ^-$ hypernuclei in the Skyrme-Hartree-Fock approach

The properties of $Ξ^-$ hypernuclei are studied systematically using a two-dimensional Skyrme-Hartree-Fock approach combined with three different $ΞN$ Skyrme forces fitted to reproduce the existing data. We explore the impurity effect of a single $Ξ^-$ hyperon on the radii, deformations, and density distributions of the nuclear core and point out qualitative differences between the different forces. We find that the $Ξ^-$ removal energy of $^{\hskip0.10em13}_{Ξp}$B [$^{12}$C(g.s.)+ $Ξ^-$(1p)] calculated by the SLX3 force is 0.7 MeV, which is in good agreement with a possible value of $0.82\pm0.17\;$MeV from the KEK E176 experiment. The theoretical prediction for this weakly bound state depends strongly on the deformation of the nuclear core, which is analyzed in detail.

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arXiv2019

Deformed $K^-$ nuclei in the Skyrme-Hartree-Fock approach

The properties of kaonic nuclei are studied using a two-dimensional Skyrme-Hartree-Fock model with a $KN$ Skyrme force. We focus in particular on the instability of the solutions for a too strong $KN$ interaction, which determines a maximum value of the kaon binding in this approach. We then analyze the change of the deformation properties of several core-deformed nuclei caused by the added kaon, and find a shrinking of the core and in some cases a complete loss of deformation.

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arXiv2018

Unitary limit and linear scaling of neutrons in harmonic trap with tuned CD-Bonn and square-well interactions

We study systems of finite-number neutrons in a harmonic trap at the unitary limit. Two very different types of neutron-neutron interactions are applied, namely, the meson-theoretic CD-Bonn potential and hard-core square-well interactions, all tuned to possess infinite scattering lengths, and with effective ranges comparable to or larger than the trap size. The potentials are renormalized to equivalent, scattering-length preserving low-momentum potentials, $V_{{\rm low}-k}$, with which the particle-particle hole-hole ring diagrams are summed to all orders to yield the ground-state energy $E_0$ of the finite neutron system. We find the ratio $E_0/E_0^{\rm free}$ (where $E_0^{\rm free}$ denotes the ground-state energy of the corresponding non-interacting system) to be remarkably independent from variations of the harmonic trap parameter, the number of neutrons, the decimation momentum of $V_{{\rm low}-k}$, and the type and effective range of the unitarity potential. Our results support a special virial linear scaling relation of $E_0$. Certain properties of Landau's quasi-particles for trapped neutrons at the unitary limit are also discussed.

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