利用基于相对论和Skyrme能量密度泛函以及壳模型的框架,计算和比较了54,56 Fe和58,60 Ni的带电中微子-核截面.根据预测的Gamow-Teller跃迁强度和现有数据、截面的多极分解以及Michel通量和Fermi-Dirac分布的平均截面,对当前中微子-核截面模型的理论不确定性进行了评估。采用不同的微观方法和模型,我们估算了DAR中微子-56 Fe的截面及其理论不确定度:<sigma>_th=(258+-57)10^{-42} cm ^2,与实验值:<sigma>_exp=(256+-108+-43)10^{-42} cm ^2非常吻合。
英文摘要:
Charged-current neutrino-nucleus cross sections for 54,56Fe and 58,60Ni are calculated and compared using frameworks based on relativistic and Skyrme energy density functionals, and the shell model. The current theoretical uncertainties in modeling neutrino-nucleus cross sections are assessed in relation to the predicted Gamow-Teller transition strength and available data, multipole decomposition of the cross sections, and cross sections averaged over the Michel flux and Fermi-Dirac distribution. Employing different microscopic approaches and models, the DAR neutrino-56Fe cross section and its theoretical uncertainty are estimated: <sigma>_th=(258+-57) 10^{-42} cm^2, in very good agreement with the experimental value: <sigma>_exp=(256+-108+-43) 10^{-42} cm^2.
Based on the relativistic mean-field effective interactions theory, and Lai dong model \citep{b37, b38, b39}, we discuss the influences of superstrong magnetic fields (SMFs) on electron Fermi energy, nuclear blinding energy, and single-particle level structure in magnetars surface. By using the method of Shell-Model Monte Carlo (SMMC), and the Random Phase Approximation (RPA) theory, we detailed analyze the neutrino energy loss rates(NELRs) by electron capture (EC) for iron group nuclei in SMFs.
Uncertainties in the production of iron-group nuclides in core-collapse supernovae from Monte Carlo variations of reaction rates
Kogakuin University(工学院大学);The University of Tokyo(东京大学);RIKEN Pioneering Research Institute (PRI)(理化学研究所先导研究本部);National Astronomical Observatory of Japan (NAOJ)(日本国立天文台);North Carolina State University(北卡罗来纳州立大学);University of Basel(巴塞尔大学);University of Hertfordshire(赫特福德大学)
Proton-rich nuclei, the so-called p-nuclei, are made in photodisintegration processes in outer shells of massive stars in the course of the final supernova explosion. Nuclear uncertainties in the production of these nuclei have been quantified in a Monte Carlo procedure. Bespoke temperature-dependent uncertainties were assigned to different types of reactions involving nuclei from Fe to Bi and all rates were varied randomly within the uncertainties. The resulting total production uncertainties of the p-nuclei are below a factor of two, with few exceptions. Key reactions dominating the final un…
The main s-process taking place in low mass stars produces about half of the elements heavier than iron. It is therefore very important to determine the importance and impact of nuclear physics uncertainties on this process. We have performed extensive nuclear reaction network calculations using individual and temperature-dependent uncertainties for reactions involving elements heavier than iron, within a Monte Carlo framework. Using this technique, we determined the uncertainty in the main s-process abundance predictions due to nuclear uncertainties link to weak interactions and neutron captu…
We have used effective reaction rates (ERR) for the helium burning reactions to predict the yield of the gamma-emitting nuclei 26Al, 44Ti, and 60Fe in core col- lapse supernovae. The variations in the predicted yields for values of the reaction rates allowed by the ERR are much smaller than obtained previously, and smaller than other uncertainties. A "filter" for supernova nucleosynthesis yields based on pre-supernova structure was used to estimate the effect of failed supernovae on the initial mass function-averaged yields; this substantially reduced the yields of all these isotopes, but the …
Nuclear uncertainties in the production of $p$ nuclei in massive stars have been quantified in a Monte Carlo procedure. Bespoke temperature-dependent uncertainties were assigned to different types of reactions involving nuclei from Fe to Bi. Their simultaneous impact was studied in postprocessing explosive trajectories for three different stellar models. It was found that the grid of mass zones in the model of a 25 $M_\odot$ star, which is widely used for investigations of $p$ nucleosynthesis, is too crude to properly resolve the detailed temperature changes required for describing the product…
Bayesian approach for many-body uncertainties in nuclear structure: Many-body perturbation theory for finite nuclei
Technische Universität Darmstadt(达姆施塔特工业大学);ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH(极端物质研究所 (EMMI),GSI 重离子研究中心有限公司);Max-Planck-Institut für Kernphysik(马克斯·普朗克核物理研究所)
We analyse the impact of the statistical uncertainties of the the nucleon-nucleon interaction, based on the Granada-2013 np-pp database, on the binding energies of the triton and the alpha particle using a bootstrap method, by solving the Faddeev equations for $^3$H and the Yakubovsky equations for $^4$He respectively. We check that in practice about 30 samples prove enough for a reliable error estimate. An extrapolation of the well fulfilled Tjon-line correlation predicts the experimental binding of the alpha particle within uncertainties.
We analyze in details the standard Primordial Nucleosynthesis scenario. In particular we discuss the key theoretical issues which are involved in a detailed prediction of light nuclide abundances, as the weak reaction rates, neutrino decoupling and nuclear rate modeling. We also perform a new analysis of available data on the main nuclear processes entering the nucleosynthesis reaction network, with particular stress on their uncertainties as well as on their role in determining the corresponding uncertainties on light nuclide theoretical estimates. The current status of theoretical versus exp…
Experimental and theoretical results of the $P_{\mathrm{CN}}$ fusion probability of reactants in the entrance channel and the $W_{\mathrm{sur}}$ survival probability against fission at deexcitation of the compound nucleus formed in heavy-ion collisions are discussed. The theoretical results for a set of nuclear reactions leading to formation of compound nuclei (CNs) with the charge number $Z=102\text{--}122$ reveal a strong sensitivity of $P_{\mathrm{CN}}$ to the characteristics of colliding nuclei in the entrance channel, dynamics of the reaction mechanism, and excitation energy of the system…
I have systematically investigated the equations of state (EOSs) in nuclear statistical equilibrium under thermodynamic conditions relevant for core collapse of massive stars by varying the bulk properties of nuclear matter, the mass data for neutron-rich nuclei, and the finite-temperature modifications of the nuclear model. It is found that the temperature dependence of the nuclear free energies has a significant impact on the entropy and nuclear composition, which affect the dynamics of core-collapse supernovae. There is a little influence from the bulk properties and the mass data. For all …
Theoretical uncertainties in the predictions of inner fission barrier heights in superheavy elements have been investigated in a systematic way for a set of state-of-the-art covariant energy density functionals which represent major classes of the functionals used in covariant density functional theory. They differ in basic model assumptions and fitting protocols. Both systematic and statistical uncertainties have been quantified where the former turn out to be larger. Systematic uncertainties are substantial in superheavy elements and their behavior as a function of proton and neutron numbers…
The s-process in massive stars, producing nuclei up to $A\approx 90$, has a different behaviour at low metallicity if stellar rotation is significant. This enhanced s-process is distinct from the s-process in massive stars around solar metallicity, and details of the nucleosynthesis are poorly known. We investigated nuclear physics uncertainties in the enhanced s-process in metal-poor stars within a Monte-Carlo framework. We applied temperature-dependent uncertainties of reaction rates, distinguishing contributions from the ground state and from excited states. We found that the final abundanc…
Quantum Monte Carlo Calculations of Light Nuclei with Fully Propagated Theoretical Uncertainties
University of Guelph(圭尔夫大学);Los Alamos National Laboratory(洛斯阿拉莫斯国家实验室);Technische Universität Darmstadt(达姆施塔特工业大学);ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH(极端物质研究所EMMI,GSI重离子研究中心有限公司);Max-Planck-Institut für Kernphysik(马克斯·普朗克核物理研究所)
We show that uncertainties in the values of the surface heavy element abundances of the Sun are the largest source of the theoretical uncertainty in calculating the p-p, pep, 8B, 13N, 15O, and 17F solar neutrino fluxes. We evaluate for the first time the sensitivity (partial derivative) of each solar neutrino flux with respect to the surface abundance of each element. We then calculate the uncertainties in each neutrino flux using `conservative (preferred)' and `optimistic' estimates for the uncertainties in the element abundances. The total conservative (optimistic) composition uncertainty in…
The non-parametric bootstrap method is used to evaluate the uncertainties of two $α$ decay formulas, the universal decay law (UDL) and the new Geiger-Nuttall law (NGNL). Such a method can simultaneously obtain the uncertainty of each parameter, the correlation between each pair of parameters, and the total, statistical, and systematic uncertainties of each formula. Both even-even (ee) nuclei and odd-A (oA) nuclei are used in the analysis. The collected data are separated into three parts: ee nuclei, oA nuclei without spin or parity change (oA\_nc), and oA nuclei with spin and/or parity change …
The systematic investigation of the ground state and fission properties of even-even actinides and superheavy nuclei with $Z=90-120$ from the two-proton up to two-neutron drip lines with proper assessment of systematic theoretical uncertainties has been performed for the first time in the framework of covariant density functional theory (CDFT). These results provide a necessary theoretical input for the r-process modeling in heavy nuclei and, in particular, for the study of fission recycling. Four state-of-the-art globally tested covariant energy density functionals (CEDFs), namely, DD-PC1, DD…
A method is suggested to decompose the statistical and systematic uncertainties from the residues between the calculation of a theoretical model and the observed data. The residues and the parameters of the model can be obtained through the standard statistical fitting procedures. The present work concentrates on the decomposition of the total uncertainty, of which the distribution corresponds to that of the residues. The distribution of the total uncertainty is considered as two normal distributions, statistical and systematic uncertainties. The standard deviation of the statistical part, σst…
The effects of the nuclear structure uncertainties on the description of processes induced by coherent scattering of neutrinos on nuclei are investigated. A reference calculation based on a specific nuclear model is defined and the cross sections and also the expected number of events produced by neutrinos generated by the explosion of a supernova in our galaxy, and by a spallation neutron source are evaluated. By changing the input parameters of the reference calculation their relevance on cross sections and on the number of the detected events is estimated. Seven spherical nuclei with differ…
Ab initio calculations in Nuclear physics for atomic nuclei require a specific knowledge of the interactions among their constituents, protons and neutrons. In particular, NN interactions can be constrained down to scale resolutions of $Δr \sim 0.6 {\rm fm}$ from the study of phase shifts below the pion production threshold. However, this allows for ambiguities and uncertainties which have an impact on finite nuclei, nuclear- and neutron-matter properties. On the other hand the nuclear many body problem is intrinsically difficult and the computational cost increases with numerical precision an…
The analysis of statistical and systematic uncertainties and their propogation to nuclear extremes has been performed. Two extremes of nuclear landscape (neutron-rich nuclei and superheavy nuclei) have been investigated. For the first extreme, we focus on the ground state properties. For the second extreme, we pay a particular attention to theoretical uncertainties in the description of fission barriers of superheavy nuclei and their evolution on going to neutron-rich nuclei.
Addendum to: QRPA uncertainties and their correlations in the analysis of neutrinoless double beta decay
在以前的文章[Phys. Rev. D 79,053001(2009)]中,我们在准粒子无规相位近似(QRPA)中估计了与无中微子双β衰变(0 nu β β)的核矩阵元(NME)相关的不确定性。这种估计包括最近对NME的独立计算,因此仍然可以提供核模型不确定性的公平代表。在这种情况下,我们比较了Ge-76中0 nu β β衰变的声明与最近在Ge-136和其他核中的负结果,并推断了在90% C. L.时允许或排除的寿命范围。我们还强调了一些问题,应加以解决,以适当地比较和结合来自不同的0 nu β β衰变候选核的结果。
We report accurate quantum Monte Carlo calculations of nuclei up to $A=16$ based on local chiral two- and three-nucleon interactions up to next-to-next-to-leading order. We examine the theoretical uncertainties associated with the chiral expansion and the cutoff in the theory, as well as the associated operator choices in the three-nucleon interactions. While in light nuclei the cutoff variation and systematic uncertainties are rather small, in $^{16}$O these can be significant for large coordinate-space cutoffs. Overall, we show that chiral interactions constructed to reproduce properties of …
Recent studies at Jefferson Lab show that there are a certain proportion of nucleons in nuclei have momenta greater than the so-called nuclear Fermi momentum $p_{F}$. Based on the transport model of nucleus-nucleus collisions at intermediate energies, nucleon high momentum caused by the neutron-proton short-range correlations in nuclei is constrained by comparing with $π$ and photon experimental data and considering some uncertainties. The high momentum cutoff value $p_{max}$ $\leq$ 2$p_{F}$ is obtained.
Heavy even-even nuclei exhibit low-energy collective excitations that are separated in scale from the microscopic (fermion) degrees of freedom. This separation of scale allows us to approach nuclear vibrations within an effective field theory (EFT). In odd-mass nuclei collective and single-particle properties compete at low energies, and this makes their description more challenging. In this article we describe odd-mass nuclei with ground-state spin $I=\sfrac{1}{2}$ by means of an EFT that couples a fermion to the collective degrees of freedom of an even-even core. The EFT relates observables …
Background: The ($α$,n) and ($α$,$γ$) reactions on $^{17,18}$O have significant impact on the neutron balance in the astrophysical $s$-process. In this scenario stellar reaction rates are required for relatively low temperatures below $T_9 \lesssim 1$. Purpose: The uncertainties of the $^{17,18}$O($α$,n)$^{20,21}$Ne reactions are investigated. Statistical model calculations are performed to study the applicability of this model for relatively light nuclei in extension to a recent review for the $20 \le A \le 50$ mass range. Method: The available experimental data for the $^{17,18}$O($α$,n)$^{2…