The European Physical Journal A最新文献_第6页

Elucidating the finite temperature quasiparticle random phase approximation 解释有限温度准粒子随机相位近似

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-26 DOI: 10.1140/epja/s10050-025-01502-y

A. Ravlić, E. M. Ney, J. Engel, N. Paar

{"title":"Elucidating the finite temperature quasiparticle random phase approximation","authors":"A. Ravlić, E. M. Ney, J. Engel, N. Paar","doi":"10.1140/epja/s10050-025-01502-y","DOIUrl":"10.1140/epja/s10050-025-01502-y","url":null,"abstract":"<div>In many astrophysical scenarios, such as core-collapse supernovae and neutron star mergers, as in well as heavy-ion collision experiments, transitions between thermally populated nuclear excited states have been shown to play an important role. Because of its simplicity and ability to extrapolate, the finite-temperature quasiparticle random phase approximation (FT-QRPA) is an efficient method for studying the properties of hot nuclei. The statistical ensembles in the FT-QRPA make the theory much richer than its zero-temperature counterpart, but also obscure the meaning of various physical quantities. In this work, we clarify several aspects of the FT-QRPA, including notation seen in the literature, and demonstrate how to extract physical quantities from the theory. To illustrate the correct treatment of finite-temperature transitions, we place special emphasis on the charge-exchange transitions described by the proton-neutron FT-QRPA (FT-PNQRPA). With the FT-PNQRPA built on the nuclear energy-density functional theory, we obtain solutions in a relativistic matrix approach and also in the non-relativistic finite amplitude method. We show that the proper treatment of de-excitations from thermally populated excited states causes the Ikeda sum rule to be fulfilled. In addition, we demonstrate the impact of these transitions on stellar electron capture (EC) rates in ( ^{58,78})Ni. While their inclusion does not affect the EC rates in ( ^{58})Ni, the rates in ( ^{78})Ni are dominated by de-excitations for temperatures (T > 0.5) MeV. In systems with a large negative Q-value, the inclusion of de-excitations within the FT-QRPA is necessary for a complete description of reaction rates at finite temperature.</div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Publisher Erratum: Ab initio Bogoliubov many-body perturbation theory: closed-form constraint on the average particle number 从头算Bogoliubov多体微扰理论：平均粒子数的封闭形式约束

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-25 DOI: 10.1140/epja/s10050-025-01506-8

P. Demol, T. Duguet, A. Tichai

引用次数: 0

Skyrme–Hartree–Fock–Bogoliubov mass models on a 3D mesh: IV. Improved description of the isospin dependence of pairing 三维网格上的Skyrme-Hartree-Fock-Bogoliubov质量模型：IV.对同位旋依赖性的改进描述

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-22 DOI: 10.1140/epja/s10050-025-01503-x

Guilherme Grams, Nikolai N. Shchechilin, Adrián Sánchez-Fernández, Wouter Ryssens, Nicolas Chamel, Stephane Goriely

{"title":"Skyrme–Hartree–Fock–Bogoliubov mass models on a 3D mesh: IV. Improved description of the isospin dependence of pairing","authors":"Guilherme Grams, Nikolai N. Shchechilin, Adrián Sánchez-Fernández, Wouter Ryssens, Nicolas Chamel, Stephane Goriely","doi":"10.1140/epja/s10050-025-01503-x","DOIUrl":"10.1140/epja/s10050-025-01503-x","url":null,"abstract":"<div>Providing reliable data on the properties of atomic nuclei and infinite nuclear matter to astrophysical applications remains extremely challenging, especially when treating both properties coherently within the same framework. Methods based on energy density functionals (EDFs) enable manageable calculations of nuclear structure throughout the entire nuclear chart and of the properties of infinite nuclear matter across a wide range of densities and asymmetries. To address these challenges, we present BSkG4, the latest Brussels-Skyrme-on-a-Grid model. It is based on an EDF of the extended Skyrme type with terms that are both momentum and density-dependent, and refines the treatment of (^1S_0) nucleon pairing gaps in asymmetric nuclear matter as inspired by more advanced many-body calculations. The newest model maintains the accuracy of earlier BSkGs for known atomic masses, radii and fission barriers with rms deviations of 0.633 MeV w.r.t. 2457 atomic masses, 0.0246 fm w.r.t. 810 charge radii, and 0.36 MeV w.r.t 45 primary fission barriers of actinides. It also improves some specific pairing-related properties, such as the (^1S_0) pairing gaps in asymmetric nuclear matter, neutron separation energies, (Q_beta ) values, and moments of inertia of finite nuclei. This improvement is particularly relevant for describing the r-process nucleosynthesis as well as various astrophysical phenomena related to the rotational evolution of neutron stars, their oscillations, and their cooling.</div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Neutrinoless (beta beta )-decay in DCEQTDA DCEQTDA中的中微子(beta beta )衰变

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-18 DOI: 10.1140/epja/s10050-025-01484-x

C. De Conti, V. dos S. Ferreira, A. R. Samana, C. A. Barbero, F. Krmpotić

{"title":"Neutrinoless (beta beta )-decay in DCEQTDA","authors":"C. De Conti, V. dos S. Ferreira, A. R. Samana, C. A. Barbero, F. Krmpotić","doi":"10.1140/epja/s10050-025-01484-x","DOIUrl":"10.1140/epja/s10050-025-01484-x","url":null,"abstract":"<div>We have recently developed a nuclear model, which is a natural extension of the pn-QRPA model, specially designed to describe double charge exchange (DCE) processes generated by two-body DCE transition operators. It is based on the Quasiparticle Tamm–Dancoff approximation (QTDA) for pn and 2p2n excitations in intermediate and final nuclei, respectively, and will be called DCEQTDA. As such, this model, having the same number of free parameters as the pn-QRPA, also brings into play the excitations of four quasiparticles to build up the final nuclear states, which are then used to evaluate the nuclear matrix elements (NMEs) for all (0^+) and (2^+) final states, including resonances, and not just for the ground state as in pn-QRPA. In addition, it allows us to evaluate: (a) the values of (Q_{{beta }{beta }}), (b) the excitation energies in final nuclei, and (c) the DCE sum rules, which are fulfilled in the DCEQTDA. So far, this model has been used mainly to calculate double beta decays with the emission of two neutrinos ((2nu beta beta )-decay). Here, we extend it to the study of these processes when no neutrinos are emitted ((0nu beta beta )-decay), evaluating them in a series of nuclei, but paying special to: (i) (^{76})Se, which have been measured recently in the GERDA and MAJORANA experiments, and (ii) (^{124})Te, for which the first direct observation of the double electron capture (2nu ) has been performed with the XENON1T dark matter detector. We obtain good agreement with the data for both the ground state and the excited states. The validity of the DCEQTDA model is checked by comparing the calculation with the experimental data for the (2nu {beta }{beta }) NMEs, and for the (Q_{{beta }{beta }}), in a series of nuclei.</div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Probing the double-beta decay of (^{104})Ru through precise Q-value measurements and nuclear matrix element calculations 通过精确的q值测量和核矩阵元素计算探测(^{104}) Ru的双β衰变

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-16 DOI: 10.1140/epja/s10050-024-01481-6

Jouni Ruotsalainen, Elina Kauppinen, Tommi Eronen, Anu Kankainen, Jenni Kotila, Maxime Mougeot

{"title":"Probing the double-beta decay of (^{104})Ru through precise Q-value measurements and nuclear matrix element calculations","authors":"Jouni Ruotsalainen, Elina Kauppinen, Tommi Eronen, Anu Kankainen, Jenni Kotila, Maxime Mougeot","doi":"10.1140/epja/s10050-024-01481-6","DOIUrl":"10.1140/epja/s10050-024-01481-6","url":null,"abstract":"<div>The Q value of the double-beta ((beta ^-beta ^-)) decay of (^{104})Ru ((Q_{beta ^-beta ^-})-value) was determined using the JYFLTRAP double Penning trap mass spectrometer employing the Phase-Imaging Ion Cyclotron Resonance (PI-ICR) method. The obtained value of 1297.705(36) keV is in agreement with the current literature value of 1299.4(27) keV but is over 70 times more precise. As a consistency check on a 100 eV level, we also measured the precisely known (^{102})Pd double-electron capture Q value, (Q_textrm{ECEC}=1203.531(92)) keV, which agrees with the literature value of 1203.47(4) keV. The measured Q value of (^{104})Ru (beta ^-beta ^-) decay was used in calculations of the phase-space factors of the double-beta decay. Also, the nuclear matrix elements were calculated using the microscopic interacting boson model (IBM-2) as a nuclear model and compared with other available results. With these theoretical calculations based on the measured Q value, the estimates for the two-neutrino and neutrinoless double-beta decay half-lives of (^{104})Ru were calculated to be (t_{1/2}^{2nu beta beta }>5.449times 10^{21}) years and (t_{1/2}^{0nu beta beta }>5.775times 10^{26}) years, respectively. The calculated (2nu beta ^-beta ^-) half-life is longer than the current experimental lower limit but short enough to be potentially within reach with future high precision experiments.</div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-024-01481-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

(alpha )-decay half-life predictions for superheavy elements through machine learning techniques 通过机器学习技术预测超重元素的（α）衰变半衰期

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-16 DOI: 10.1140/epja/s10050-025-01494-9

S. Madhumitha Shree, M. Balasubramaniam

{"title":"(alpha )-decay half-life predictions for superheavy elements through machine learning techniques","authors":"S. Madhumitha Shree, M. Balasubramaniam","doi":"10.1140/epja/s10050-025-01494-9","DOIUrl":"10.1140/epja/s10050-025-01494-9","url":null,"abstract":"<div>The stability and synthesis of superheavy nuclei are critically influenced by the accurate prediction of (alpha )-decay half-lives. As an alternative to traditional models and empirical formulae, we employ the XGBoost machine learning algorithm for predicting the (alpha )-decay half-lives of superheavy nuclei. For training the machine learning algorithm, the experimental half-lives of 344 nuclides in the mass range of 106 (le A le 261) and atomic numbers (52 le Z le 107) are used. Intricate correlations between nuclear features (Q value of the decay, mass, charge, neutron numbers) and half-lives are developed while training the XGBoost model with existing experimental data. The model performance is then assessed by comparing the predictions with experimental data and other empirical estimates. The trained model is found to have the least mean square deviation with respect to other empirical formulae. The trained model is then used to calculate the half lives of superheavy nuclei. The obtained results indicate that, in the superheavy element (SHE) region, XGBoost makes very effective predictions for the (alpha )-decay half-lives. The impact of physics features is demonstrated with SHAP (SHapley Additive exPlanations) summary plots.</div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of the nuclear equation of state on the formation of twin stars 核状态方程对孪生星形成的影响

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-11 DOI: 10.1140/epja/s10050-025-01497-6

Nai-Bo Zhang, Bao-An Li

引用次数: 0

Cross section and isomeric ratio measurements along with covariance analysis for the (n,2n) reactions on 120,130Te 120,130Te上（n,2n）反应的截面和同分异构体比测量及协方差分析

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-08 DOI: 10.1140/epja/s10050-025-01501-z

Junhua Luo, Long He, Liang Zhou, Li Jiang

{"title":"Cross section and isomeric ratio measurements along with covariance analysis for the (n,2n) reactions on 120,130Te","authors":"Junhua Luo, Long He, Liang Zhou, Li Jiang","doi":"10.1140/epja/s10050-025-01501-z","DOIUrl":"10.1140/epja/s10050-025-01501-z","url":null,"abstract":"<div>In this report, the cross sections of nuclear reactions 120Te(n,2n)119m,gTe and 130Te(n,2n)129m,gTe induced by d-T neutrons and their isomeric ratios (σm/σg) were measured. The pure ground state cross section (σg, for 130Te) deducted the effect from its isomeric transition. The off-line gamma-spectrum technique in conjunction with a high purity germanium (HPGe) detector was utilized to obtain the activity of the product radionuclides. The experiments were performed at the China Academy of Engineering Physics (CAEP). The K-400 neutron generator was used to produce neutrons with an energy of 13–15 MeV. The neutron fluence was monitored using the nuclear reaction 93Nb(n,2n)92mNb, which had a threshold energy that was similar to the reaction under study. A detailed covariance analysis was carried out for the cross sections of nuclear reactions 120Te(n,2n)119m,gTe and 130Te(n,2n)129m,gTe. All the measured cross sections were also determined using the theoretical calculation program TALYS-1.96 code with six level density models. The measured cross section values were compared with the results reported in the literature, along with the theoretical estimates and the evaluation results.</div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Negative moments as the signature of the radial density at small distances 负矩作为小距离径向密度的特征

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-08 DOI: 10.1140/epja/s10050-025-01496-7

M. Atoui, M. Hoballah, M. Lassaut, J. Van de Wiele

{"title":"Negative moments as the signature of the radial density at small distances","authors":"M. Atoui, M. Hoballah, M. Lassaut, J. Van de Wiele","doi":"10.1140/epja/s10050-025-01496-7","DOIUrl":"10.1140/epja/s10050-025-01496-7","url":null,"abstract":"<div>The present paper proposes a robust evaluation of any radial density at small distances using negative-order radial moments evaluated in momentum space. This evaluation provides a valuable insight into the behavior of a given radial density in the vicinity of (r=0), and puts strong emphasis on the importance of measuring form factors at large squared four-momentum transfer, a domain essential for the determination of negative order moments. A specific attention is paid to the regularization scheme directly affecting the numerical determination of the radial density’s parametrization. The proposed method is applied to non-relativistic study cases of the nucleon electric ((G_{En}, G_{Ep})), and proton magnetic (G_{Mp}) form factors. The validation is performed through comparison of the results of the approach to the analytically determined Maclaurin expansion - in the vicinity of (r=0) - of the radial density function. The method is also applied to the relativistic Dirac form factor ({{F_{1p}}}) of the proton. In such a non-trivial case, the Maclaurin development might not exist for the radial density, rendering the determination from the proposed method extremely important.</div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 2","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01496-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143361665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Isovector properties of effective finite-range nuclear interactions 有效有限范围核相互作用的等矢量性质

IF 2.6 3区物理与天体物理

The European Physical Journal A Pub Date : 2025-02-07 DOI: 10.1140/epja/s10050-025-01491-y

D. Davesne, J. Navarro, A. Pastore, Y. Lallouet

引用次数: 0