Pub Date : 2026-04-01Epub Date: 2026-01-18DOI: 10.1016/j.nuclphysa.2026.123336
F.A. Martynenko, A.V. Eskin, A.P. Martynenko
Within the quark model and hyperspherical method, the bound states of four heavy quarks and antiquarks (tetraquarks) are investigated. In hyperradial approximation, the Schrödinger equation is reduced to a one-dimensional equation after averaging over angles in hyperspace. This equation is solved numerically and analytically within the variational method. The hyperfine structure of the energy spectrum is calculated. To increase the accuracy of the calculation, corrections to the energy levels from the QCD generalization of the Breit Hamiltonian are taken into account.
{"title":"Heavy tetraquarks in the hyperspherical approach to a four-body system","authors":"F.A. Martynenko, A.V. Eskin, A.P. Martynenko","doi":"10.1016/j.nuclphysa.2026.123336","DOIUrl":"10.1016/j.nuclphysa.2026.123336","url":null,"abstract":"<div><div>Within the quark model and hyperspherical method, the bound states of four heavy quarks and antiquarks (tetraquarks) are investigated. In hyperradial approximation, the Schrödinger equation is reduced to a one-dimensional equation after averaging over angles in hyperspace. This equation is solved numerically and analytically within the variational method. The hyperfine structure of the energy spectrum is calculated. To increase the accuracy of the calculation, corrections to the energy levels from the QCD generalization of the Breit Hamiltonian are taken into account.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123336"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-21DOI: 10.1016/j.nuclphysa.2026.123339
Chandan Sarma, Praveen C. Srivastava
In this work, we explore the entanglement structure of two nuclei, 20Ne and 22Na using single-orbital entanglement entropy within the No-Core Shell Model (NCSM) framework for two realistic interactions, INOY and N3LO. We begin with the determination of the optimal frequencies based on the variation of ground-state (g.s.) binding energy with NCSM parameters, Nmax and ℏΩ, followed by an analysis of the total single-orbital entanglement entropy, Stot, for the g.s. of 20Ne and 22Na. Our results show that Stot increases with Nmax and decreases with ℏΩ after reaching a maximum. We use Stot to guide the selection of an additional set of optimal frequencies that can enhance electromagnetic transition strengths. We also calculate the low-energy spectra and Stot for four low-lying states of 20Ne and six low-lying states of 22Na. Finally, we calculate a few E2 and one M1 transition strengths, finding that N3LO provides better results for ) and INOY performs well for the transition in the 22Na nucleus while considering the first set of optimal frequencies. We also observe that the second set of optimal frequencies enhances electromagnetic transition strengths, particularly for the states with large and comparable Stot. Also, for both nuclei, the Stot for INOY and N3LO are close while considering the second set of optimal frequencies, suggesting that the calculated Stot are more dependent on ℏΩ than the interactions employed for the same model space defined by the Nmax parameter.
{"title":"Investigation of entanglement in N=Z nuclei within no-core shell model","authors":"Chandan Sarma, Praveen C. Srivastava","doi":"10.1016/j.nuclphysa.2026.123339","DOIUrl":"10.1016/j.nuclphysa.2026.123339","url":null,"abstract":"<div><div>In this work, we explore the entanglement structure of two <span><math><mrow><mi>N</mi><mo>=</mo><mi>Z</mi></mrow></math></span> nuclei, <sup>20</sup>Ne and <sup>22</sup>Na using single-orbital entanglement entropy within the No-Core Shell Model (NCSM) framework for two realistic interactions, INOY and N<sup>3</sup>LO. We begin with the determination of the optimal frequencies based on the variation of ground-state (g.s.) binding energy with NCSM parameters, <em>N</em><sub>max</sub> and ℏΩ, followed by an analysis of the total single-orbital entanglement entropy, <em>S<sub>tot</sub></em>, for the g.s. of <sup>20</sup>Ne and <sup>22</sup>Na. Our results show that <em>S<sub>tot</sub></em> increases with <em>N</em><sub>max</sub> and decreases with ℏΩ after reaching a maximum. We use <em>S<sub>tot</sub></em> to guide the selection of an additional set of optimal frequencies that can enhance electromagnetic transition strengths. We also calculate the low-energy spectra and <em>S<sub>tot</sub></em> for four low-lying states of <sup>20</sup>Ne and six low-lying states of <sup>22</sup>Na. Finally, we calculate a few <em>E</em>2 and one <em>M</em>1 transition strengths, finding that N<sup>3</sup>LO provides better results for <span><math><mrow><mi>B</mi><mo>(</mo><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>5</mn><mn>1</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>3</mn><mn>1</mn><mo>+</mo></msubsup></mrow></math></span>) and INOY performs well for the <span><math><mrow><mi>B</mi><mo>(</mo><mi>M</mi><mn>1</mn><mo>;</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>1</mn><mn>1</mn><mo>+</mo></msubsup><mo>)</mo></mrow></math></span> transition in the <sup>22</sup>Na nucleus while considering the first set of optimal frequencies. We also observe that the second set of optimal frequencies enhances electromagnetic transition strengths, particularly for the states with large and comparable <em>S<sub>tot</sub></em>. Also, for both nuclei, the <em>S<sub>tot</sub></em> for INOY and N<sup>3</sup>LO are close while considering the second set of optimal frequencies, suggesting that the calculated <em>S<sub>tot</sub></em> are more dependent on ℏΩ than the interactions employed for the same model space defined by the <em>N</em><sub>max</sub> parameter.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123339"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-15DOI: 10.1016/j.nuclphysa.2026.123333
Serdar Ünlü
A detailed quasi-particle random phase approximation (QRPA) analysis of two neutrino double electron capture transitions to the ground states and first excited states of 78Se and 130Xe is given in the present work. The experimental data related to the intermediate and final excited states have been reproduced using the adjustable strength parameters. The nuclear matrix elements and half-lives for two neutrino double electron capture have been calculated and compared with other calculations and corresponding experimental data. It can be said that the present approximation is usually successful in reproducing the experimental half-lives for two neutrino double electron capture.
{"title":"Two neutrino double electron capture of 78Kr and 130Ba in the QRPA framework","authors":"Serdar Ünlü","doi":"10.1016/j.nuclphysa.2026.123333","DOIUrl":"10.1016/j.nuclphysa.2026.123333","url":null,"abstract":"<div><div>A detailed quasi-particle random phase approximation (QRPA) analysis of two neutrino double electron capture transitions to the ground states and first excited states of <sup>78</sup>Se and <sup>130</sup>Xe is given in the present work. The experimental data related to the intermediate and final excited states have been reproduced using the adjustable strength parameters. The nuclear matrix elements and half-lives for two neutrino double electron capture have been calculated and compared with other calculations and corresponding experimental data. It can be said that the present approximation is usually successful in reproducing the experimental half-lives for two neutrino double electron capture.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123333"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
In this study, we examine how an isospin asymmetric nuclear medium affects the properties of pseudoscalar () and vector () mesons under different temperature values and degrees of isospin asymmetry, using the light-front quark model. To simulate the in-medium modifications of the constituent quark masses, we employ the chiral SU(3) quark mean field model. Our analysis focuses on evaluating the effective masses, weak decay constants, and distribution amplitudes (DAs) of B mesons in isospin-asymmetric nuclear matter. The calculated vacuum values of the B meson masses and decay constants show good agreement with existing experimental data, validating our approach to study the medium effects within the same framework.
{"title":"Impact of isospin asymmetric nuclear medium on pseudoscalar and vector B mesons","authors":"Tanisha, Satyajit Puhan, Navpreet Kaur, Harleen Dahiya, Arvind Kumar","doi":"10.1016/j.nuclphysa.2026.123330","DOIUrl":"10.1016/j.nuclphysa.2026.123330","url":null,"abstract":"<div><div>In this study, we examine how an isospin asymmetric nuclear medium affects the properties of pseudoscalar (<span><math><mrow><msup><mi>B</mi><mo>+</mo></msup><mo>,</mo><msup><mi>B</mi><mn>0</mn></msup></mrow></math></span>) and vector (<span><math><mrow><msup><mi>B</mi><mrow><mo>*</mo><mo>+</mo></mrow></msup><mo>,</mo><msup><mi>B</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup></mrow></math></span>) mesons under different temperature values and degrees of isospin asymmetry, using the light-front quark model. To simulate the in-medium modifications of the constituent quark masses, we employ the chiral SU(3) quark mean field model. Our analysis focuses on evaluating the effective masses, weak decay constants, and distribution amplitudes (DAs) of <em>B</em> mesons in isospin-asymmetric nuclear matter. The calculated vacuum values of the <em>B</em> meson masses and decay constants show good agreement with existing experimental data, validating our approach to study the medium effects within the same framework.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123330"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-16DOI: 10.1016/j.nuclphysa.2026.123331
E.Ya. Paryev
The possibility to study the nature of the famous charged bottomonium-like states Zb(10610) and Zb(10650), which is by far the best known, from their inclusive photoproduction off nuclei near the kinematic threshold is investigated within the collision model based on the nuclear spectral function. The model accounts for Zb(10610) ± and Zb(10650) ± production in direct photon–nucleon interactions as well as four different scenarios for their intrinsic configurations: compact tetraquarks, molecules of the two open-beauty mesons and two mixtures of both of them for each of Zb state. We calculate within these scenarios the absolute and relative excitation functions on 12C and 184W nuclei at photon energies of 61–90 GeV, the absolute momentum differential cross sections and ratios of them for their production off these target nuclei at laboratory polar angles of 0∘–5∘ and for photon energy of 75 GeV as well as the A-dependences of the transparency ratios for the Zb(10610) ± mesons at photon energy of 75 GeV. We show that the absolute and relative observables considered reveal distinct sensitivity to the Zb(10610) ± and Zb(10650) ± internal structures. Therefore, they might be useful for the determination of these structures from the comparison of them with the experimental data from the future high-precision experiments at the upcoming experimental facilities, such as the planned high-luminosity electron-ion colliders in the United States and China.
{"title":"Insights into the exotic charged states Zb(10610) and Zb(10650) from their photoproduction off nuclei","authors":"E.Ya. Paryev","doi":"10.1016/j.nuclphysa.2026.123331","DOIUrl":"10.1016/j.nuclphysa.2026.123331","url":null,"abstract":"<div><div>The possibility to study the nature of the famous charged bottomonium-like states <em>Z<sub>b</sub></em>(10610) and <em>Z<sub>b</sub></em>(10650), which is by far the best known, from their inclusive photoproduction off nuclei near the kinematic threshold is investigated within the collision model based on the nuclear spectral function. The model accounts for <em>Z<sub>b</sub></em>(10610)<sup> ± </sup> and <em>Z<sub>b</sub></em>(10650)<sup> ± </sup> production in direct photon–nucleon interactions as well as four different scenarios for their intrinsic configurations: compact tetraquarks, molecules of the two open-beauty mesons and two mixtures of both of them for each of <em>Z<sub>b</sub></em> state. We calculate within these scenarios the absolute and relative excitation functions on <sup>12</sup>C and <sup>184</sup>W nuclei at photon energies of 61–90 GeV, the absolute momentum differential cross sections and ratios of them for their production off these target nuclei at laboratory polar angles of 0<sup>∘</sup>–5<sup>∘</sup> and for photon energy of 75 GeV as well as the A-dependences of the transparency ratios for the <em>Z<sub>b</sub></em>(10610)<sup> ± </sup> mesons at photon energy of 75 GeV. We show that the absolute and relative observables considered reveal distinct sensitivity to the <em>Z<sub>b</sub></em>(10610)<sup> ± </sup> and <em>Z<sub>b</sub></em>(10650)<sup> ± </sup> internal structures. Therefore, they might be useful for the determination of these structures from the comparison of them with the experimental data from the future high-precision experiments at the upcoming experimental facilities, such as the planned high-luminosity electron-ion colliders in the United States and China.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123331"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-18DOI: 10.1016/j.nuclphysa.2026.123337
Jin-Yi Pang, Yuting Wang, Wanchen Lei
We study the ultraviolet regularization of the modified Lüscher formula for two-body systems with long-range interactions and demonstrate that, after imposing a physical renormalization condition, the resulting finite-volume spectrum is independent on the cutoff. The interaction is separated into a known long-range part, taken as a Yukawa potential, and a short-range part parameterized by a polynomial contact expansion, for which we keep the leading S-wave low energy constant (LEC). Although the Yukawa interaction is regular, ultraviolet divergences arise in the infinite volume modified K-matrix and in the finite volume loop function (the modified zeta function H), making a regularization unavoidable. We introduce a smooth form factor and determine LEC by fixing the physical S-wave scattering length. With this prescription, the modified K-matrix and finite volume loop function are calculated directly. We find that the modified quantization condition produces the finite volume energy levels correctly near left-hand cut across a wide range of cutoff values. It provides strong evidence that the modified Lüscher formula is a regulator-independent tool for extracting short-range information from lattice spectra in systems with long-range forces.
{"title":"Cutoff independence of the modified Lüscher formula for two-hadron system","authors":"Jin-Yi Pang, Yuting Wang, Wanchen Lei","doi":"10.1016/j.nuclphysa.2026.123337","DOIUrl":"10.1016/j.nuclphysa.2026.123337","url":null,"abstract":"<div><div>We study the ultraviolet regularization of the modified Lüscher formula for two-body systems with long-range interactions and demonstrate that, after imposing a physical renormalization condition, the resulting finite-volume spectrum is independent on the cutoff. The interaction is separated into a known long-range part, taken as a Yukawa potential, and a short-range part parameterized by a polynomial contact expansion, for which we keep the leading S-wave low energy constant (LEC). Although the Yukawa interaction is regular, ultraviolet divergences arise in the infinite volume modified K-matrix and in the finite volume loop function (the modified zeta function H), making a regularization unavoidable. We introduce a smooth form factor <span><math><msup><mi>e</mi><mrow><mo>−</mo><msup><mi>p</mi><mn>2</mn></msup><mo>/</mo><msup><mstyle><mi>Λ</mi></mstyle><mn>2</mn></msup></mrow></msup></math></span> and determine LEC by fixing the physical S-wave scattering length. With this prescription, the modified K-matrix and finite volume loop function are calculated directly. We find that the modified quantization condition produces the finite volume energy levels correctly near left-hand cut across a wide range of cutoff values. It provides strong evidence that the modified Lüscher formula is a regulator-independent tool for extracting short-range information from lattice spectra in systems with long-range forces.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123337"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-14DOI: 10.1016/j.nuclphysa.2026.123334
Evelyn Schuller , Horia Paşca
Understanding the potential energy landscape of fissioning nuclei is crucial for improving nuclear models and predicting fission fragment formation. In this study, we extract the potential energy in the mass coordinate from experimental mass distributions of Cf and Fm isotopes, assuming statistical equilibrium in the fissioning nucleus. By comparing the extracted potentials with those predicted by the statistical scission-point model, we investigate the validity of the equilibrium assumption and the accuracy of fission fragment formation at scission.
{"title":"Extraction of the potential energy in mass asymmetry coordinate from experimental mass distributions of f and m isotopes","authors":"Evelyn Schuller , Horia Paşca","doi":"10.1016/j.nuclphysa.2026.123334","DOIUrl":"10.1016/j.nuclphysa.2026.123334","url":null,"abstract":"<div><div>Understanding the potential energy landscape of fissioning nuclei is crucial for improving nuclear models and predicting fission fragment formation. In this study, we extract the potential energy in the mass coordinate from experimental mass distributions of Cf and Fm isotopes, assuming statistical equilibrium in the fissioning nucleus. By comparing the extracted potentials with those predicted by the statistical scission-point model, we investigate the validity of the equilibrium assumption and the accuracy of fission fragment formation at scission.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123334"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-21DOI: 10.1016/j.nuclphysa.2026.123340
Sucheta Adhikari , Indrani Bhadra , Chinmay Basu
Sub barrier heavy ion fusion reaction has been studied extensively in relation to back angle elastic and quasi elastic scattering. In this work, this technique is applied to alpha induced reactions with medium heavy nuclei which has relevance to the study of p nuclei synthesis. The elastic alpha scattering cross-sections at 170 degrees on 94Mo, 90Zr, 110Cd and 128Te at below barrier energies are taken as test cases to extract the barrier distributions and the fusion cross-sections for alpha particles. The single Gaussian barrier distribution model which has been recently applied to heavy ion fusion reactions is used in this work for alpha induced reactions and is found to be beneficial in comparison to the multi parameter alpha optical model.
{"title":"Alpha particle induced compound nuclear reaction cross-sections from sub barrier back angle elastic scattering","authors":"Sucheta Adhikari , Indrani Bhadra , Chinmay Basu","doi":"10.1016/j.nuclphysa.2026.123340","DOIUrl":"10.1016/j.nuclphysa.2026.123340","url":null,"abstract":"<div><div>Sub barrier heavy ion fusion reaction has been studied extensively in relation to back angle elastic and quasi elastic scattering. In this work, this technique is applied to alpha induced reactions with medium heavy nuclei which has relevance to the study of p nuclei synthesis. The elastic alpha scattering cross-sections at 170 degrees on <sup>94</sup>Mo, <sup>90</sup>Zr, <sup>110</sup>Cd and <sup>128</sup>Te at below barrier energies are taken as test cases to extract the barrier distributions and the fusion cross-sections for alpha particles. The single Gaussian barrier distribution model which has been recently applied to heavy ion fusion reactions is used in this work for alpha induced reactions and is found to be beneficial in comparison to the multi parameter alpha optical model.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123340"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-13DOI: 10.1016/j.nuclphysa.2026.123327
S. Madhumitha Shree, M. Balasubramaniam
In this study, we introduce a machine learning approach to predict the logarithmic α-decay half-lives of ground-state emitters with a specific focus on extrapolating predictions to superheavy nuclei. The input data comprised of 344 experimentally determined α-decay half-lives. We utilized two complementary methodologies: XGBoost, an efficient ensemble learning algorithm, and PySR, a symbolic regression tool that generates interpretable empirical formulae. According to the SHAP (SHapley Additive exPlanations) explanation of the XGBoost model, features such as and were found to be very influential, which were chosen as input features for symbolic regression. PySR was trained to provide a simple empirical expression to calculate the logarithmic half-lives of α-decay. The derived expressions showed excellent agreement with the existing experimental data. Finally, we assess the extrapolation power of the models by predicting half-lives for the α-decay of various isotopes of superheavy nuclei of and . The results illustrate the power and physical accuracy of both approaches, making them suitable for guiding nuclear data evaluation in regions where experimental information is limited or unavailable.
{"title":"Machine learning and symbolic regression-based modeling of α-decay half-lives for superheavy nuclei","authors":"S. Madhumitha Shree, M. Balasubramaniam","doi":"10.1016/j.nuclphysa.2026.123327","DOIUrl":"10.1016/j.nuclphysa.2026.123327","url":null,"abstract":"<div><div>In this study, we introduce a machine learning approach to predict the logarithmic <em>α</em>-decay half-lives of ground-state emitters with a specific focus on extrapolating predictions to superheavy nuclei. The input data comprised of 344 experimentally determined <em>α</em>-decay half-lives. We utilized two complementary methodologies: XGBoost, an efficient ensemble learning algorithm, and PySR, a symbolic regression tool that generates interpretable empirical formulae. According to the SHAP (SHapley Additive exPlanations) explanation of the XGBoost model, features such as <span><math><msqrt><mi>Z</mi></msqrt></math></span> and <span><math><mrow><mn>1</mn><mo>/</mo><msqrt><mi>Q</mi></msqrt></mrow></math></span> were found to be very influential, which were chosen as input features for symbolic regression. PySR was trained to provide a simple empirical expression to calculate the logarithmic half-lives of <em>α</em>-decay. The derived expressions showed excellent agreement with the existing experimental data. Finally, we assess the extrapolation power of the models by predicting half-lives for the <em>α</em>-decay of various isotopes of superheavy nuclei of <span><math><mrow><mi>Z</mi><mo>=</mo><mn>107</mn></mrow></math></span> and <span><math><mrow><mi>Z</mi><mo>=</mo><mn>110</mn></mrow></math></span>. The results illustrate the power and physical accuracy of both approaches, making them suitable for guiding nuclear data evaluation in regions where experimental information is limited or unavailable.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123327"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2026-04-01Epub Date: 2026-01-13DOI: 10.1016/j.nuclphysa.2026.123332
Larry Zamick
The previously considered (2j-1) rule for cross-conjugate pairs [44Sc, 52Mn] and [84Nb, 96Ag] is extended to a lighter pair [20F,24Na]. We also consider self-conjugate 8Li. It is noted and explained why the (2j-1) state in 20F is not isomeric.
{"title":"The (2j-1) rule for isomerism in odd-odd nuclei : Flip-flop behavior of cross-conjugates","authors":"Larry Zamick","doi":"10.1016/j.nuclphysa.2026.123332","DOIUrl":"10.1016/j.nuclphysa.2026.123332","url":null,"abstract":"<div><div>The previously considered (2j-1) rule for cross-conjugate pairs [<sup>44</sup>Sc, <sup>52</sup>Mn] and [<sup>84</sup>Nb, <sup>96</sup>Ag] is extended to a lighter pair [<sup>20</sup>F,<sup>24</sup>Na]. We also consider self-conjugate <sup>8</sup>Li. It is noted and explained why the (2j-1) state in <sup>20</sup>F is not isomeric.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1068 ","pages":"Article 123332"},"PeriodicalIF":2.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145993538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
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