Possible shape coexistence in Ne isotopes and the impurity effect of Λ hyperon

The possible shape coexistence in even-even Ne isotopes and the impurity effects of the sΛ and pΛ hyperons are explored employing the multidimensionally constrained relativistic-mean-field(MDC-RMF) model with the PK1 parameter set for the N N interaction and PK1-Y1 for the ΛN interaction. The quadrupole deformation potential energy surfaces(PESs), nuclear deformations, nuclear radii, binding energies, and density distributions of the hypernuclei and core nuclei are examined. The possible shape coexistence in ^(24,26,28)Ne is predicted with small energy differences of 140, 336, and 128 keV, respectively, between the two local energy minima. Different impurity effects of the sΛand pΛ hyperons are revealed. The sΛ hyperon exhibits clear shrinkage effects, which reduce the nuclear size and facilitate a spherical nuclear shape. The prolate pΛhyperon on the 1/2^(-)[110] orbital renders the nuclear shape more prolate, while the oblate pΛ hyperon on the 3/2^(-)[101] or 1/2^(-)[101] orbital renders the nuclei more oblate. Moreover, the Λ hyperon can increase the probabilities of the shape coexistence by reducing the energy differences between the two local energy minima, although the shape coexistence may disappear owing to the vanishment of one energy minimum on the flat energy surface.

Possible shape coexistence in odd-A Ne isotopes and the impurity effects ofΛhyperons

In this study, shape evolution and possible shape coexistence are explored in odd-A Ne isotopes in the framework of the multidimensionally constrained relativistic-mean-field(MDC-RMF)model. By introducing ~sΛ and phyperons, the impurity effects on the nuclear shape, energy, size, and density distribution are investigated.For the NN interaction, the PK1 parameter set is adopted, and for the ΛN interaction, the PK1-Y1 parameter set is used. The nuclear ground state and low-lying excited states are determined by blocking the unpaired odd neutron in different orbitals around the Fermi surface. Moreover, the potential energy curves(PECs), quadrupole deformations,nuclear r.m.s. radii, binding energies, and density distributions for the core nuclei as well as the corresponding hy pernuclei are analyzed. By examining the PECs, possibilities for shape coexistence inNe and a triple shape coexistence inNe are found. In terms of the impurity effects ofΛhyperons, as noted for even-even Ne hypernuclear isotopes, the shyperon exhibits a clear shrinkage effect, which reduces the nuclear size and results in a more spherical nuclear shape. The phyperon occupying the 1/2~-[110]orbital is prolate, which causes the nuclear shape to be more prolate, and the phyperon occupying the 3/2~-[101] orbital displays an oblate shape, which drives the nuclei to be more oblate.

The influence of isotope substitution of neon atom on the integral cross sections of rotational excitation in Ne-Na2 collisions

This paper applies the multiple ellipsoid model to the 16Ne （20Ne, 28Ne, 34Ne）-Na2 collision systems, and calcu- lates integral cross sections for rotational excitation at the incident energy of 190 meV. It can be seen that the accuracy of the integral cross sections can be improved by increasing the number of equipotential ellipsoid surfaces. Moreover, by analysing the differences of these integral cross sections, it obtains the change rules of the integral cross sections with the increase of rotational angular quantum number j＇, and with the change of the mass of isotope substitution neon atom. Finally, the contribution of different regions of the potential to inelastic cross sections for 20Ne-Na2 collision system is investigated at relative incident energy of 190 meV.