In this work we use microscopic Nucleon-Nucleus Optical Potentials (OP) to analyze elastic scattering data for the differential cross section of the $^{78}$Kr (p,p) $^{78}$Kr reaction, with the goal of extracting the matter radius and estimating the neutron skin, quantities that are both needed to determine the slope parameter $L$ of the nuclear symmetry energy. Our analysis is performed with the factorized version of the microscopic OP obtained in a previous series of papers within the Watson multiple scattering theory at the first order of the spectator expansion, which is based on the underlying nucleon-nucleon dynamics and is free from phenomenological inputs. Differently from our previous applications, the proton and neutron densities are described with a two-parameter Fermi (2pF) distribution, which makes the extraction of the matter radius easier and allows us to make a meaningful comparison with the original analysis, that was performed with the Glauber model. With standard minimization techniques we performed data analysis and extracted the matter radius and the neutron skin. Our analysis produces a matter radius of $R_m^{\rm (rms)} = 4.12$ fm, in good agreement with previous matter radii extracted from $^{76}$Kr and $^{80}$Kr, and a neutron skin of $ΔR_{np} \simeq - 0.1$ fm, compatible with a previous analysis. Our factorized microscopic OP, supplied with 2pF densities, is a valuable tool to perform the analysis of the experimental differential cross section and extract information such as matter radius and neutron skin. Without any free parameters it provides a reasonably good description of the experimental differential cross section for scattering angles up to $\approx$ 40 degrees. Compared to the Glauber model our OP can be applied to a wider range of scattering angles and allows one to probe the nuclear systems in a more internal region.
Quadrupole moments and charge radii in cadmium isotopes are studied from a microscopic perspective. The results obtained from self-consistent deformed Hartree-Fock+BCS calculations with Skyrme forces are compared with isomer and isotope shifts measured from high resolution laser spectroscopy experiments. The microscopic calculations reproduce fairly well the main features observed in those isotopes that include the linear increase with the neutron number of the quadrupole moments of the 11/2- isomers, as well as the parabolic behavior of the mean-square charge radii difference between isomers …
In this work, Na isotopes with mass varying from $A=$ 20 to 31 have been studied using DJ16A, JISP16 and N3LO microscopic effective interactions in the $sd$-shell. These effective interactions are derived for $sd$-shell using no-core shell model wavefunctions and a unitary transformation method. We have also performed calculation with IMSRG effective interactions targeted for a particular nucleus. The studies include a detailed analysis of ground state binding energy, low-lying spectra, and electromagnetic properties such as reduced electric quadrupole transition strengths, quadrupole and magn…
We present predictions for proton skins based on isospin-asymmetric equations of state derived microscopically from high-precision chiral few-nucleon interactions. Moreover, we investigate the relation between the neutron skin of a nucleus and the difference between the proton radii of the corresponding mirror nuclei.
Nuclear Charge Radii and Electric Quadrupole Moments
用动力学微观模型计算了20< Z < 98$的偶偶核的均方半径和电四极矩的同位素位移。采用单粒子Nilsson势和Seo修正项参数,BCS形式中的对力和局域近似中的长程相互作用。集体哈密顿量是使用生成坐标法(GCM)与高斯重叠近似(GOA)。原子核的势能由微观-宏观Strutinsky能和零点振动项组成。一个液滴模型被用来作为宏观部分的潜力。以BCS波函数为生成函数,以四极和十六极形变为生成坐标。
Microscopic mechanism of the Fayans pairing for the enhancement of charge radii
The University of Tokyo(东京大学);RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)(理化学研究所交叉理论与数学科学中心 (iTHEMS));Università degli Studi di Milano(米兰大学);INFN, Sezione di Milano(意大利国家核物理研究所,米兰分部);Universitat de Barcelona(巴塞罗那大学);Institut de Ciències del Cosmos, Universitat de Barcelona(巴塞罗那大学宇宙科学研究所);University of Aizu(会津大学);RIKEN Nishina Center(理化学研究所仁科研究中心)
The mesoscopic nature of the atomic nucleus gives rise to a wide array of macroscopic and microscopic phenomena. The size of the nucleus is a window into this duality: while the charge radii globally scale as $A^{1/3}$, their evolution across isotopic chains reveals unanticipated structural phenomena [1-3]. The most ubiquitous of these is perhaps the Odd-Even Staggering (OES) [4]: isotopes with an odd number of neutrons are usually smaller in size than the trend of their even-neutron neighbours suggests. This OES effect varies with the number of protons and neutrons and poses a significant cha…
Matter radii from interaction cross sections using microscopic nuclear densities
Facility for Rare Isotope Beams, Michigan State University(稀有同位素束设施,密歇根州立大学);Department of Physics and Astronomy, Michigan State University(物理与天文学系,密歇根州立大学);Université Paris-Saclay, CNRS/IN2P3, IJCLab(巴黎萨克雷大学,法国国家科学研究中心/法国国家原子核及粒子物理研究所,IJCLab);Institute for Theoretical Physics II, University of Erlangen(埃尔朗根大学理论物理第二研究所)
We calculate neutron star's moment of inertia and deformabilities using various microscopic equations of state for nuclear and hybrid star configurations. Correlations between the various observables are examined and we confirm several universal relations. We focus in particular on the constraints for the neutron star radii imposed by a determination of the average tidal deformability of the binary neutron star system GW170817. We find compatible radii between 12 and 13 kilometers and identify the suitable equations of state.
Prolate-oblate shape competition and impact on charge radii in Bk isotopes
School of Physics, Zhengzhou University(郑州大学物理学院);State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University(北京大学物理学院核物理与核技术国家重点实验室)
A feed-forward neural network model is trained to calculate the nuclear charge radii. The model trained with input data set of proton and neutron number $Z,N$, the electric quadrupole transition strength $B(E2)$ from the first excited 2$^+$ state to the ground state, together with the symmetry energy. The model reproduces well not only the isotope dependence of charge radii, but also the kinks of charge radii at the neutron magic numbers $N=82$ for Sn and Sm isotopes, and also $N=126$ for Pb isotopes. The important role of $B(E2)$ value is pointed out to reproduce the kink of the isotope depen…
Difference in proton radii of mirror nuclei as a possible surrogate for the neutron skin
最近有人提出,镜像核电荷半径的差异与丰中子核的中子皮厚度和对称能$L$的斜率成正比[B.A. Brown Phys. Rev. Lett. 119,122502(2017)]。中子皮的确定对核物理和天体物理有重要意义。虽然电弱探针的使用提供了一个很大程度上与模型无关的中子皮的测定,实验的挑战是巨大的。因此,镜像核的电荷半径的差异可以被用作中子皮的替代物的可能性是一个受欢迎的替代方案。为了检验这一假设的有效性,我们进行计算的基础上,一组相对论能量密度泛函,跨越一个广泛的区域的值的$L$。我们的研究结果证实,不同的缺中子镍同位素和它们相应的镜像核的电荷半径的差异确实是强烈相关的中子皮厚度和$L$。此外,考虑到中子星的各种性质也对$L$敏感,镜像核的电荷半径差与低质量中子星的半径之间出现了数据对数据的关系。
The analysis of self-consistency and proton-neutron interaction effects in the buildup of differential charge radii has been carried out in covariant density functional theoretical calculations without pairing interaction. Two configurations of the $^{218}$Pb nucleus, generated by the occupation of the neutron $1i_{11/2}$ and $2g_{9/2}$ subshells, are compared with the ground state configuration in $^{208}$Pb. The interaction of added neutron(s) and the protons forming the $Z=82$ proton core is responsible for a major contribution to the buildup of differential charge radii. It depends on the …
Precise Determination of Electric Quadrupole Moments and Isotope Shift Constants of Yb$^+$ in Pursuance of Probing Fundamental Physics and Nuclear Radii
An analytical equation for calculating radial dose of heavy ions in water is introduced by Awad et al. (Applied Radiation and Isotopes, 142 (2018) 135-142. It is simple alternative to Monte Carlo code and is a promising code, however, still needs refinement. Refinement was added through adjusting radial dose integration upper limit which gives the effective delta-ray range, rmax and ions penumbra radius in water as well. Radial dose distributions for 85 ions forming fifteen energy groups from 0.25 to 24 MeV/n were studied. By employing the effective delta-ray range, it was possible to get more…
We studied recent observation data of pulsar masses and radii of PSR J0740$+$6620, PSR J0348$+$0432, and PSR J1614$-$2230 from different measurements, based on the extended version of $σ$-$ ω$ model. Throughout our analysis, we assumed that these pulsars are maximal-mass compact stars, thus we applied the core approximation. Based on the linear relation between the microscopic and macroscopic parameters of compact stars evaluated by our model, we estimated the average Landau mass $m_L = 752.46^{+49.1}_{-42.5}$ MeV and compressibility $K = 261.7^{+57.2}_{-28.0}$ MeV.
University of Debrecen(德布勒森大学);Extreme Light Infrastructure - Nuclear Physics (ELI-NP)(极轻基础设施-核物理研究所);Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)(赫里亚·胡鲁贝伊核物理与核工程研发国家研究所);International Atomic Energy Agency (IAEA)(国际原子能机构);Clemson University(克莱姆森大学);University of Manchester(曼彻斯特大学);Université Paris-Saclay(巴黎萨克雷大学);Johannes Gutenberg-Universität Mainz(约翰内斯·古腾堡美因茨大学);Michigan State University(密歇根州立大学);Max-Planck-Institut für Kernphysik(马克斯·普朗克核物理研究所);Paul Scherrer Institute(保罗谢尔研究所);Technische Universität Darmstadt(达姆施塔特工业大学)
The ${}^{12}\mathrm{C} + {}^{12}\mathrm{C}$ fusion reaction plays a vital role in the explosive phenomena of the universe. The resonances in the Gamow window rule its reaction rate and products. Hence, the determination of the resonance parameters by nuclear models is indispensable as the direct measurement is not feasible. Here, for the first time, we report the resonances in the ${}^{12}\mathrm{C} + {}^{12}\mathrm{C}$ fusion reaction described by a full-microscopic nuclear model. The model plausibly reproduces the measured low-energy astrophysical $S$-factors and predicts the resonances in t…
A thick neutron skin emerges from the first determination of root mean square radii of the proton distributions for $^{17-22}$N from charge changing cross section measurements around 900$A$ MeV at GSI. Neutron halo effects are signaled for $^{22}$N from an increase in the proton and matter radii. The radii suggest an unconventional shell gap at $N$ = 14 arising from the attractive proton-neutron tensor interaction, in good agreement with shell model calculations. $Ab$ $initio$, in-medium similarity re-normalization group, calculations with a state-of-the-art chiral nucleon-nucleon and three-nu…
The Nuclear Level Density and the Determination of Thermonuclear Rates for Astrophysics
在核天体物理研究中,对远离稳定核的截面的预测是一个非常重要的问题。在最近的计算中,核能级密度-作为统计模型(Hauser-Feshbach)的一个重要组成部分-显示出最大的不确定性。我们提出了一个全球参数化的核能级密度的基础上的后移费米气体形式主义。使用一个依赖于能量的能级密度参数$a$和来自Möller等人最近的FRDM质量公式的微观修正导致在质量范围$20\le A \le 245$内的中子分离能处的能级密度的高度改进的拟合。使用适当的微观修正质量公式的重要性进行了强调。所得的能级描述非常适合于天体物理学应用。能级密度还可以提供仅对高密度的激发态正确的统计模型的适用性的线索。利用上述描述,人们可以得出一个"地图",为稳定和不稳定的核与中性和带电粒子的反应模型的适用性。
The first determination of the nuclear charge radius by laser spectroscopy for a five-electron system is reported. This is achieved by combining high-accuracy ab initio mass-shift calculations and a high-resolution measurement of the isotope shift in the $2s^2 2p\, ^2\mathrm{P}_{1/2} \rightarrow 2s^2 3s\, ^2\mathrm{S}_{1/2}$ ground state transition in boron atoms. Accuracy is increased by orders of magnitude for the stable isotopes $^{10,11}$B and the results are used to extract their difference in the mean-square charge radius $\langle r^2_\mathrm{c}\rangle^{11} - \langle r^2_\mathrm{c}\rangl…
We extract the proton magnetic radius from the high-precision electron-proton elastic scattering cross section data. Our theoretical framework combines dispersion analysis and chiral effective field theory and implements the dynamics governing the shape of the low-$Q^2$ form factors. It allows us to use data up to $Q^2\sim$ 0.5 GeV$^2$ for constraining the radii and overcomes the difficulties of empirical fits and $Q^2 \rightarrow 0$ extrapolation. We obtain a magnetic radius $r_M^p$ = 0.850 $\pm$0.001 (fit 68%) $\pm$0.010 (theory full range) fm, significantly different from earlier results ob…