Non-Observation of the Production of Superheavy Nuclei in the Reaction of $^{86]$Kr with $^{208}$Pb

Correlation between alpha-decay Energies of Superheavy Nuclei Involving Effect of Symmetry Energy

A formula for the relationship between the $α$-decay energies ($Q$ values) of superheavy nuclei (SHN) is presented, which is composed of the effects of Coulomb energy and symmetry energy. It can be employed not only to validate the experimental observations and measurements to a large extent, but also to predict the $Q$ values of heaviest SHN with a high accuracy generally which will be very useful for future experiments. Furthermore, the shell closures in superheavy region and the effect of the symmetry energy on the stability of SHN against $α$-decay are discussed with the help of this formu…

Potential energy surfaces and fission fragment mass yields of even-even superheavy nuclei

Potential energy surfaces and fission barriers of superheavy nuclei are analyzed in the macroscopic-microscopic model. The Lublin-Strasbourg Drop (LSD) is used to obtain the macroscopic part of the energy, whereas the shell and pairing energy corrections are evaluated using the Yukawa-folded potential. A standard flooding technique has been used to determine the barrier heights. It was shown the Fourier shape parametrization containing only three deformation parameters reproduces well the nuclear shapes of nuclei on their way to fission. In addition, the non-axial degree of freedom is taken in…

超重核中的弱衰变

Weak decays in superheavy nuclei

该研究采用相对论核密度泛函理论与优化相互作用的准粒子无规相位近似，系统计算Z=101–118核的EC/β±衰变，发现一级禁戒1⁻跃迁普遍主导，并识别44个具有可观弱衰变分支的核。

Natural superheavy nuclei in astrophysical data

The paper presents the summary data of the authors' research within the framework of the OLIMPIYA project (the Russian acronym of {\bf OLI}viny iz {\bf M}eteoritov --- {\bf P}oisk tyazholykh {\bf I} sverkhtyazholykh {\bf YA}der / Olivines from meteorites: Search for heavy and superheavy nuclei) and results of track analysis for heavy cosmic ray nuclei (\emph{Z} = 26--129) in olivine crystals from meteorites using an original processing technique. A total of 21,743 tracks of nuclei heavier than iron have been identified in meteoritic matter to date to form the largest database within this charg…

alpha decay half-lives of new superheavy nuclei within a generalized liquid drop model

The alpha decay half-lives of the recently produced isotopes of the 112, 114, 116 and 118 nuclei and decay products have been calculated in the quasi-molecular shape path using the experimental Qalpha value and a Generalized Liquid Drop Model including the proximity effects between nucleons in the neck or the gap between the nascent fragments. Reasonable estimates are obtained for the observed alpha decay half-lives. The results are compared with calculations using the Density-Dependent M3Y effective interaction and the Viola-Seaborg-Sobiczewski formulae. Generalized Liquid Drop Model predicti…

中等激发能下超重核中的多步粒子发射概率

Multi-step particle emission probabilities in superheavy nuclei at moderate excitation energies

本研究利用 Monte Carlo 方法和微观核能级密度计算超重核多步粒子蒸发概率，并通过有效温度改进 Jackson 公式，同时提出平均发射粒子动能的解析估计。

朝向119号元素的复合超重核存活概率

Survival Probabilities of Compound Superheavy Nuclei Towards Element 119

本研究基于微观能量相关裂变位垒分析复合超重核存活概率，结合双核系统模型重现已有反应数据，估算两种合成119号元素的反应截面与最优束流能量，为新元素合成提供参考。

Superheavy Elements in the Magic Islands

Recent microscopic calculation based on the density functional theory predicts long-lived superheavy elements in a variety of shapes, including spherical, axial and triaxial configurations. Only when N=184 is approached one expects superheavy nuclei that are spherical in their ground states. Magic islands of extra-stability have been predicted to be around Z=114, 124 or, 126 with N=184, and Z=120, with N=172. However, the question of whether the fission-survived superheavy nuclei with high Z and N would live long enough for detection or, undergo alpha-decay in a very short time remains open. I…

探索超重核中的巨单极共振：一个理论视角

Exploring the giant monopole resonance in superheavy nuclei: A theoretical perspective

本文利用相对论平均场框架下的扩展托马斯-费米近似，计算超重核（Z=110-118）的结合能、半径及巨单极共振，并与多种方法比较，进而预测其核压缩性。

On the Stability of Superheavy Nuclei

Potential energy surfaces of even-even superheavy nuclei are evaluated within the macroscopic-microscopic approximation. A very rapidly converging analytical Fourier-type shape parametrization is used to describe nuclear shapes throughout the periodic table, including those of fissioning nuclei. The Lublin Strasbourg Drop and another effective liquid-drop type mass formula are used to determine the macroscopic part of nuclear energy. The Yukawa-folded single-particle potential, the Strutinsky shell-correction method, and the BCS approximation for including pairing correlations are used to obta…

Hot fusion reactions with deformed nuclei for synthesis of superheavy nuclei: an extension of the fusion-by-diffusion model

The fusion-by-diffusion model proposed by Swiatecki {\it et al.} [Phys. Rev. C71, 014602 (2005)] has provided a simple and convenient tool to estimate evaporation residue cross sections for superheavy nuclei. I extend this model by taking into account deformation of the target nucleus, and discuss the role of orientation of deformed target in hot fusion reactions at energies around the Coulomb barrier. To this end, I introduce an injection point for the diffusion process over an inner barrier which depends on the orientation angle. I apply this model to the $^{48}$Ca+$^{248}$Cm reaction and sh…

Cold reaction valleys in the radioactive decay of superheavy {286}^112, {292}^114 and {296}^116 nuclei

Cold reaction valleys in the radioactive decay of superheavy nuclei {286}^112, {292}^114 and {296}^116 are studied taking Coulomb and Proximity Potential as the interacting barrier. It is found that in addition to alpha particle, 8^Be, 14^C, 28^Mg, 34^Si, 50^Ca, etc. are optimal cases of cluster radioactivity since they lie in the cold valleys. Two other regions of deep minima centered on 208^Pb and 132^Sn are also found. Within our Coulomb and Proximity Potential Model half-life times and other characteristics such as barrier penetrability, decay constant for clusters ranging from alpha parti…

通往超重核的路径

Paths to Superheavy Nuclei

本文总结2024年FRIB-TA专题项目关于超重核研究的讨论，评估理论现状，确定必要发展以指导实验和产生机制，并强调建立理论界的重要性。

New approach for alpha decay half-lives of superheavy nuclei and applicability of WKB approximation

The alpha decay half-lives of recently synthesized superheavy nuclei (SHN) are calculated by applying a new approach which estimates them with the help of their neighbors based on some simple formulas. The estimated half-life values are in very good agreement with the experimental ones, indicating the reliability of the experimental observations and measurements to a large extent as well as the predictive power of our approach. The second part of this work is to test the applicability of the Wentzel-Kramers-Brillouin (WKB) approximation for the quantum mechanical tunneling probability. We calc…

Alpha-decay half-lives and Q_alpha values of superheavy nuclei

The alpha-decay half-lives of recently synthesized superheavy nuclei (SHN) are investigated based on a unified fission model (UFM) where a new method to calculate the assault frequency of alpha-emission is used. The excellent agreement with the experimental data indicates the UFM is a useful tool to investigate these alpha-decays. It is found that the half-lives become more and more insensitive to the Q_alpha values as the atomic number increases on the whole, which is favorable for us to predict the half-lives of SHN. In addition, a formula is suggested to compute the Q_alpha values for the n…

Coupled-channels calculations for nuclear reactions: from exotic nuclei to superheavy elements

Atomic nuclei are composite systems, and they may be dynamically excited during nuclear reactions. Such excitations are not only relevant to inelastic scattering but they also affect other reaction processes such as elastic scattering and fusion. The coupled-channels approach is a framework which can describe these reaction processes in a unified manner. It expands the total wave function of the system in terms of the ground and excited states of the colliding nuclei, and solves the coupled Shrödinger equations to obtain the $S$-matrix, from which several cross sections can be constructed. Thi…

Nonaxial-octupole effect in superheavy nuclei

The triaxial-octupole Y$_{32}$ correlation in atomic nuclei has long been expected to exist but experimental evidence has not been clear. We find, in order to explain the very low-lying 2$^-$ bands in the transfermium mass region, that this exotic effect may manifest itself in superheavy elements. Favorable conditions for producing triaxial-octupole correlations are shown to be present in the deformed single-particle spectrum, which is further supported by quantitative Reflection Asymmetric Shell Model calculations. It is predicted that the strong nonaxial-octupole effect may persist up to the…

Microscopic study of higher-order deformation effects on the ground states of superheavy nuclei around $^{270}$Hs

We study the effects of higher-order deformations $β_λ$ ($λ=4,6,8,$ and $10$) on the ground state properties of superheavy nuclei (SHN) near the doubly magic deformed nucleus $^{270}$Hs by using the multidimensionally-constrained (MDC) relativistic mean-field (RMF) model with five effective interactions PC-PK1, PK1, NL3$^{*}$, DD-ME2, and PKDD. The doubly magic properties of $^{270}$Hs are featured by the large energy gaps at $N=162$ and $Z=108$ in the single-particle spectra. By investigating the binding energies and single-particle levels of $^{270}$Hs in multidimensional deformation space, …

Theoretical study of the synthesis of superheavy nuclei with Z= 119 and 120 in heavy-ion reactions with trans-uranium targets

By using a newly developed di-nuclear system model with a dynamical potential energy surface---the DNS-DyPES model, hot fusion reactions for synthesizing superheavy nuclei (SHN) with the charge number Z = 112-120 are studied. The calculated evaporation residue cross sections are in good agreement with available data. In the reaction 50Ti+249Bk -> (299-x)119 + xn, the maximal evaporation residue (ER) cross section is found to be about 0.11 pb for the 4n-emission channel. For projectile-target combinations producing SHN with Z=120, the ER cross section increases with the mass asymmetry in the in…

Predictions on the alpha decay chains of superheavy nuclei with Z =121 within the range 290 $\leq$ A $\leq$ 339

A systematic study on the alpha decay half lives of various isotopes of superheavy element \textit{Z} = 121 within the range 290 $\leq$ A $\leq$ 339 is presented for the first time using Coulomb and proximity potential model for deformed nuclei (CPPMDN). The calculated $α$ decay half lives of the isotopes within our formalism match well with the values computed using Viola-Seaborg systematic, Universal curve of Poenaru et al., and the analytical formula of Royer. In our study by comparing the $α$ decay half lives with the spontaneous fission half lives, we have predicted $2α$ chain from $^{309…

Superheavy nuclei with the vector self-coupling of the $ω$-meson in the relativistic mean-field theory

We have studied properties and shell structure of the superheavy elements from Z=102 to Z=120 within the framework of the RMF theory. The region of study spans nuclides with neutron numbers N=150-190. The Lagrangian model NL-SV1 with the inclusion of the vector self-coupling of the omega-meson has been employed in this work. We have performed RMF + BCS calculations for an axially deformed configuration of nuclei. The ground-state binding energies, single-particle properties and quadrupole deformation of nuclei have been obtained from the mean-field minimizations. Two-neutron separation energie…

Systematic Study of Survival Probability of Excited Superheavy Nuclei

The stability of excited superheavy nuclei (SHN) with $100 \leq Z \leq 134$ against neutron emission and fission is investigated by using a statistical model. In particular, a systematic study of the survival probability against fission in the 1n-channel of these SHN is made. In present calculations the neutron separation energies and shell correction energies are consistently taken from the calculated results of the finite range droplet model which predicts an island of stability of SHN around Z=115 and N=179. It turns out that this island of stability persists for excited SHN in the sense th…

Time-dependent Hartree-Fock plus Langevin approach for hot fusion reactions to synthesize the $Z=120$ superheavy element

We develop a novel approach to fusion reactions for syntheses of superheavy elements, which combines the time-dependent Hartree-Fock (TDHF) method with a dynamical diffusion model based on the Langevin equation. In this approach, the distance of the closest approach for the capture process is estimated within the TDHF approach, which is then plugged into the dynamical diffusion model as an initial condition. We apply this approach to hot fusion reactions leading to formation of the element $Z=120$, that is, the $^{48}$Ca+$^{254,257}$Fm, $^{51}$V+$^{249}$Bk, and $^{54}$Cr+$^{248}$Cm reactions. …

Constraining the equation of state of nuclear matter from competition of fusion and quasi-fission in the reactions leading to production of the superheavy elements

The mechanism of fusion hindrance, an effect preventing the synthesis of superheavy elements in the reactions of cold and hot fusion, is investigated using the Boltzmann-Uehling-Uhlenbeck equation, where Coulomb interaction is introduced. A strong sensitivity is observed both to the modulus of incompressibility of symmetric nuclear matter, controlling the competition of surface tension and Coulomb repulsion, and to the stiffness of the density-dependence of symmetry energy, influencing the formation of the neck prior to scission. The experimental fusion probabilities were for the first time us…

Superheavy Elements: Beyond the 7th Period in the Periodic Table

What is the heaviest element? In order to address this question, the elements up to $Z=118$ have been synthesized by now by using heavy-ion fusion reactions. This has completed the 7th period in the periodic table of elements, and new attempts have been commenced in aiming at syntheses of the elements in the 8th period. In this article, we review the current status and future challenges in the research field of superheavy elements, putting some emphasis on perspectives from the nuclear reaction theory.

Alpha-decay properties of superheavy elements $Z=113-125$ in the relativistic mean-field theory with vector self-coupling of $ω$ meson

We have investigated properties of $α$-decay chains of recently produced superheavy elements Z=115 and Z=113 using the new Lagrangian model NL-SV1 with inclusion of the vector self-coupling of $ω$ meson in the framework of the relativistic mean-field theory. It is shown that the experimentally observed alpha-decay energies and half-lives are reproduced well by this Lagrangian model. Further calculations for the heavier elements with Z=117-125 show that these nuclei are superdeformed with a prolate shape in the ground state. A superdeformed shell-closure at Z=118 lends an additional binding and…

Main restrictions in the synthesis of new superheavy elements: quasifission or/and fusion-fission

The synthesis of superheavy elements stimulates the effort to study the peculiarities of the complete fusion with massive nuclei and to improve theoretical models in order to extract knowledge about reaction mechanism in heavy ion collisions at low energies. We compare the theoretical results of the compound nucleus (CN) formation and evaporation residue (ER) cross sections obtained for the $^{48}$Ca+$^{248}$Cm and $^{58}$Fe+$^{232}$Th reactions leading to the formation of the isotopes A=296 and A=290, respectively, of the new superheavy element Lv (Z=116). The ER cross sections, which can be …

利用改进的经验公式研究从跨锡区到超重区的集团放射性

Cluster radioactivity from trans-tin to superheavy region using an improved empirical formula

本文通过引入同位旋和角动量改进集团放射性半衰期经验公式，系统研究跨锡至超重核区的集团发射与α衰变等竞争过程，提出适用于宽广核素范围的精确半衰期估算方法。

重核与超重核的衰变谱学研究

Decay spectroscopy of heavy and superheavy nuclei

本文综述了利用分离后衰变谱学（DSAS）研究Z=99至Z=118重核与超重核的近年实验进展，梳理了超重核各研究方向的现有覆盖范围与成果。

Future of superheavy element research: Which nuclei could be synthesized within the next few years?

Low values of the fusion cross sections and very short half-lives of nuclei with Z$>$120 put obstacles in synthesis of new elements. Different nuclear reactions (fusion of stable and radioactive nuclei, multi-nucleon transfers and neutron capture), which could be used for the production of new isotopes of superheavy (SH) elements, are discussed in the paper. The gap of unknown SH nuclei, located between the isotopes which were produced earlier in the cold and hot fusion reactions, can be filled in fusion reactions of $^{48}$Ca with available lighter isotopes of Pu, Am, and Cm. Cross sections f…

Possible Existence of Extremely Neutron-Rich Superheavy Nuclei in Neutron Star Crusts Under a Superstrong Magnetic Field

We investigate outer crust compositions for a wide range of magnetic field strengths, up to $B\simeq 4\times10^{18}$ G, employing the latest experimental nuclear masses supplemented with various mass models. The essential effects of the magnetic field are twoholds: 1) Enhancement of electron fraction, which is connected to that of protons via the charge neutrality condition, due to the Landau-Rabi quantization of electron motion perpendicular to the field, namely, neutron-richness is suppressed for a given pressure. As a result, 2) nuclei can exist at higher pressures without dripping out neut…