Pub Date : 2025-11-24DOI: 10.1016/j.nuclphysa.2025.123291
K. Jyothish, M.R. Asmitha, Rhine A.K. Kumar
The deformation energy landscape of 232Th nucleus along its fission path is investigated using the Lublin-Strasbourg Drop (LSD) model with the Fourier shape parametrization. The nuclear surface is represented by a truncated Fourier series in terms of collective coordinates associated with elongation (q2), mass asymmetry (q3), and neck formation (q4). This parametrization offers enhanced flexibility in describing fission pathways and the complex shape transitions of the thorium isotope up to the scission point. Studying fission characteristics in actinide nuclei such as 232Th is crucial to advance our understanding of nuclear energy production and structure.
{"title":"Nuclear shape transition of Th isotope at fission limits: a fourier shape parametrization approach","authors":"K. Jyothish, M.R. Asmitha, Rhine A.K. Kumar","doi":"10.1016/j.nuclphysa.2025.123291","DOIUrl":"10.1016/j.nuclphysa.2025.123291","url":null,"abstract":"<div><div>The deformation energy landscape of <sup>232</sup>Th nucleus along its fission path is investigated using the Lublin-Strasbourg Drop (LSD) model with the Fourier shape parametrization. The nuclear surface is represented by a truncated Fourier series in terms of collective coordinates associated with elongation (<em>q</em><sub>2</sub>), mass asymmetry (<em>q</em><sub>3</sub>), and neck formation (<em>q</em><sub>4</sub>). This parametrization offers enhanced flexibility in describing fission pathways and the complex shape transitions of the thorium isotope up to the scission point. Studying fission characteristics in actinide nuclei such as <sup>232</sup>Th is crucial to advance our understanding of nuclear energy production and structure.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1067 ","pages":"Article 123291"},"PeriodicalIF":2.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682168","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 measured both the pre-scission and post-scission neutron multiplicities for the 31P + 170Er reaction at excitation energies in the range of 62-84 MeV, using the National Array of Neutron Detectors (NAND) at Inter University Accelerator Centre (IUAC), New Delhi. Theoretical calculations to reproduce the measured neutron multiplicities have been performed using the dynamical model code VECLAN. These calculations show that the dissipation strength parameter (β) increases with excitation energy. Dynamical model calculations also have been performed using HICOL code to understand the fusion dynamics and formation time. It has been observed that transitioning from an asymmetric to a symmetric entrance channel leads to a gradual increase in the compound nucleus formation time, accompanied by more emission of neutrons during its formation.
{"title":"Investigating entrance channel effect through the measurement of neutron multiplicity in mass region a ≈ 200","authors":"Neha Dhanda , Ashok Kumar , Chetan Sharma , Amninderjeet Kaur , Basant Sura , Komal , Amit , Kiran , B.R. Behera , P. Sugathan , Akhil Jhinghan , N. Saneesh , K.S. Golda , Mohit Kumar , Rishabh Parjapati , Avitesh Agrawal , Ishika Sharma , H.P. Sharma , S.K. Chamoli , Swapna Balkrishna , Lakhyajit Sarma","doi":"10.1016/j.nuclphysa.2025.123271","DOIUrl":"10.1016/j.nuclphysa.2025.123271","url":null,"abstract":"<div><div>In this study, we measured both the pre-scission and post-scission neutron multiplicities for the <sup>31</sup>P + <sup>170</sup>Er reaction at excitation energies in the range of 62-84 MeV, using the National Array of Neutron Detectors (NAND) at Inter University Accelerator Centre (IUAC), New Delhi. Theoretical calculations to reproduce the measured neutron multiplicities have been performed using the dynamical model code VECLAN. These calculations show that the dissipation strength parameter (<em>β</em>) increases with excitation energy. Dynamical model calculations also have been performed using HICOL code to understand the fusion dynamics and formation time. It has been observed that transitioning from an asymmetric to a symmetric entrance channel leads to a gradual increase in the compound nucleus formation time, accompanied by more emission of neutrons during its formation.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1067 ","pages":"Article 123271"},"PeriodicalIF":2.5,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682172","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 : 2025-11-20DOI: 10.1016/j.nuclphysa.2025.123287
Faisal Etminan
The deuteron-deuteron (D-D) thermonuclear reaction rates in metallic environments, accounting for electron screening effects, are calculated using S-factor functions derived from fits to low-energy D-D reaction data. For this purpose, a fitted S-factor model based on the NACRE compilation is employed, which constrains the energy range applicable to Big Bang nucleosynthesis (BBN) for the 2H(d, p)3H and 2H(d, n)3He reactions. The Maxwellian-averaged thermonuclear reaction rates, relevant to astrophysical plasmas at temperatures ranging from 106 K to 1010 K (or 1.3 × 108 K), are presented in tabular formats. The effects of electron screening are phenomenologically analyzed, with screening energy (Ue) values of 100, 400, 750, 1000, and 1250 eV being employed for this purpose. This selection of values is grounded in theoretical and experimental studies conducted to date. Ultimately, the numerical analysis reveals that the ratio of the screened reaction rate to the unscreened reaction rate can be expressed by the numerical formula for both the 2H(d, p)3H and 2H(d, n)3He reactions.
{"title":"The role of the screening potential in the deuteron-deuteron thermonuclear reaction rates","authors":"Faisal Etminan","doi":"10.1016/j.nuclphysa.2025.123287","DOIUrl":"10.1016/j.nuclphysa.2025.123287","url":null,"abstract":"<div><div>The deuteron-deuteron (D-D) thermonuclear reaction rates in metallic environments, accounting for electron screening effects, are calculated using S-factor functions derived from fits to low-energy D-D reaction data. For this purpose, a fitted S-factor model based on the NACRE compilation is employed, which constrains the energy range applicable to Big Bang nucleosynthesis (BBN) for the <sup>2</sup>H(<em>d, p</em>)<sup>3</sup>H and <sup>2</sup>H(<em>d, n</em>)<sup>3</sup>He reactions. The Maxwellian-averaged thermonuclear reaction rates, relevant to astrophysical plasmas at temperatures ranging from 10<sup>6</sup> K to 10<sup>10</sup> K (or 1.3 × 10<sup>8</sup> K), are presented in tabular formats. The effects of electron screening are phenomenologically analyzed, with screening energy (<em>U<sub>e</sub></em>) values of 100, 400, 750, 1000, and 1250 eV being employed for this purpose. This selection of values is grounded in theoretical and experimental studies conducted to date. Ultimately, the numerical analysis reveals that the ratio of the screened reaction rate to the unscreened reaction rate can be expressed by the numerical formula <span><math><mrow><mi>exp</mi><mrow><mo>(</mo><mn>4.70</mn><mo>+</mo><mn>6.50</mn><mrow><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow><msub><mi>U</mi><mi>e</mi></msub><mo>/</mo><msub><mi>T</mi><mn>9</mn></msub><mo>)</mo></mrow></mrow></math></span> for both the <sup>2</sup>H(<em>d, p</em>)<sup>3</sup>H and <sup>2</sup>H(<em>d, n</em>)<sup>3</sup>He reactions.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1066 ","pages":"Article 123287"},"PeriodicalIF":2.5,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615022","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 : 2025-11-20DOI: 10.1016/j.nuclphysa.2025.123288
Mudasir Ahmad, Amit Bindra
Quantum shape-phase transitions in medium and heavy mass nuclei remain key benchmarks for testing nuclear models. Building on recent machine learning (ML) studies [1–3], we introduce a hybrid framework that integrates empirical systematics, Interacting Boson Approximation (IBA-1), and Light Gradient Boosting Machine (LightGBM) predictions. A composite sensitivity parameter, S = ▾R4/2 × B(E2; 0⁺ → 2⁺) is proposed, coupling deformation dynamics with quadrupole collectivity. Applied to rare-earth nuclei (Z = 58–68, N = 84–102) Ȿ exhibits a sharp peak near N ∼ 90, providing a distinct indicator of the U(5)–SU(3) phase transition. LightGBM reproduces excitation energies and B(E2) values with high accuracy across 47 isotopes, while extrapolations identify 154Gd and 156Dy as critical-point candidates and highlight 156Nd, 150Gd and 152,168Dy as priority cases for measurement. The reliability of our approach is underscored by SHAP (Shapley additive explanation) analysis, which highlights the dominant role of the Casten factor and neutron number, thereby reinforcing the physical interpretability of the model. These findings establish Ȿ as a sensitive probe of shape evolution and demonstrate the promise of physics-guided ML–theory frameworks for informing future spectroscopic studies. Our methodology is inherently scalable and can be systematically extended across the nuclear chart to explore shape coexistence and shell evolution, offering a robust pathway for future ML–IBA studies in diverse structural regimes.
{"title":"Nuclear structure of medium and heavy mass nuclei: From collectivity trends to machine learning approaches","authors":"Mudasir Ahmad, Amit Bindra","doi":"10.1016/j.nuclphysa.2025.123288","DOIUrl":"10.1016/j.nuclphysa.2025.123288","url":null,"abstract":"<div><div>Quantum shape-phase transitions in medium and heavy mass nuclei remain key benchmarks for testing nuclear models. Building on recent machine learning (ML) studies [1–3], we introduce a hybrid framework that integrates empirical systematics, Interacting Boson Approximation (IBA-1), and Light Gradient Boosting Machine (LightGBM) predictions. A composite sensitivity parameter, <em>S</em> = ▾R<sub>4/2</sub> × <em>B</em>(E2; 0⁺ → 2⁺) is proposed, coupling deformation dynamics with quadrupole collectivity. Applied to rare-earth nuclei (<em>Z</em> = 58–68, <em>N</em> = 84–102) <em>Ȿ</em> exhibits a sharp peak near N ∼ 90, providing a distinct indicator of the U(5)–SU(3) phase transition. LightGBM reproduces excitation energies and B(E2) values with high accuracy across 47 isotopes, while extrapolations identify <sup>154</sup>Gd and <sup>156</sup>Dy as critical-point candidates and highlight <sup>156</sup>Nd, <sup>150</sup>Gd and <sup>152,168</sup>Dy as priority cases for measurement. The reliability of our approach is underscored by SHAP (Shapley additive explanation) analysis, which highlights the dominant role of the Casten factor and neutron number, thereby reinforcing the physical interpretability of the model. These findings establish <em>Ȿ</em> as a sensitive probe of shape evolution and demonstrate the promise of physics-guided ML–theory frameworks for informing future spectroscopic studies. Our methodology is inherently scalable and can be systematically extended across the nuclear chart to explore shape coexistence and shell evolution, offering a robust pathway for future ML–IBA studies in diverse structural regimes.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1067 ","pages":"Article 123288"},"PeriodicalIF":2.5,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617195","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 : 2025-11-19DOI: 10.1016/j.nuclphysa.2025.123285
Dharmendra Singh , Amritraj Mahato , Nitin Sharma , Rajesh K. Sahoo , Rahul Mahato , Lupteindu Chhura , Mohd. Usman , Rahbar Ali , M. Afzal Ansari , M. Ismail
Excitation functions for the 16O + 45Sc reaction were measured over 39.2-114.5 MeV, focusing on the production of medically important radioisotopes 57Co and 51Cr. 57Co (half-life: 271.8 days) is a γ-emitter widely used in medical imaging, and Mössbauer spectroscopy, while 51Cr (half-life: 27.7 days) is employed in blood volume and glomerular filtration rate assessment. In the present work, stacked foil technique was employed followed by offline γ-ray spectroscopy. The measured excitation functions for 57Co and 51Cr were compared with the predictions from the statistical model code PACE4. The experimental cross-sections of these radioisotopes were found to be significantly higher than the PACE4 predictions. These enhancements are attributed to the contribution of incomplete fusion processes which are not accounted in PACE4, highlighting an alternative pathway for radioisotope production via complete and incomplete fusion mechanisms at above barrier energies. While, the cross-section yields for both the radioisotopes were found to be high, the results indicate that the 16O+45Sc reaction is more suitable for 51Cr production due to its cleaner excitation function.
{"title":"Production of 57Co and 51Cr isotopes for medical application in the interaction of 16O projectile with 45Sc target","authors":"Dharmendra Singh , Amritraj Mahato , Nitin Sharma , Rajesh K. Sahoo , Rahul Mahato , Lupteindu Chhura , Mohd. Usman , Rahbar Ali , M. Afzal Ansari , M. Ismail","doi":"10.1016/j.nuclphysa.2025.123285","DOIUrl":"10.1016/j.nuclphysa.2025.123285","url":null,"abstract":"<div><div>Excitation functions for the <sup>16</sup>O + <sup>45</sup>Sc reaction were measured over 39.2-114.5 MeV, focusing on the production of medically important radioisotopes <sup>57</sup>Co and <sup>51</sup>Cr. <sup>57</sup>Co (half-life: 271.8 days) is a <em>γ</em>-emitter widely used in medical imaging, and Mössbauer spectroscopy, while <sup>51</sup>Cr (half-life: 27.7 days) is employed in blood volume and glomerular filtration rate assessment. In the present work, stacked foil technique was employed followed by offline <em>γ</em>-ray spectroscopy. The measured excitation functions for <sup>57</sup>Co and <sup>51</sup>Cr were compared with the predictions from the statistical model code PACE4. The experimental cross-sections of these radioisotopes were found to be significantly higher than the PACE4 predictions. These enhancements are attributed to the contribution of incomplete fusion processes which are not accounted in PACE4, highlighting an alternative pathway for radioisotope production via complete and incomplete fusion mechanisms at above barrier energies. While, the cross-section yields for both the radioisotopes were found to be high, the results indicate that the <sup>16</sup>O+<sup>45</sup>Sc reaction is more suitable for <sup>51</sup>Cr production due to its cleaner excitation function.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1066 ","pages":"Article 123285"},"PeriodicalIF":2.5,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615021","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 : 2025-11-18DOI: 10.1016/j.nuclphysa.2025.123284
S. Hinge, P. Singh, K. Churi, M. Hemalatha
The study presents calculated cross sections for proton-induced reactions on 180,182,183,184,186W isotopes for the production of 180,182,183,184,186Re using the TALYS-2.0 nuclear reaction code. The optical model potentials were calculated using Koning-Delaroche (KD) model for protons scattering from 180,182,183,184,186W isotopes. Using the potentials, the calculated differential elastic scattering and total reaction cross sections were compared with corresponding data where available and were found to be in good agreement. Further, the calculated (p,n) reaction cross sections were calculated using nuclear level densities from both the back-shifted Fermi gas model (BFM) and the microscopic Hartree-Fock-Bogoliubov (HFB) approaches. The calculated (p,n) reaction cross sections compare well with data and TENDL-2023 for 186Re for which data are available, while for the isotopes, 180,182,183Re, predictions have been made. In addition, production yields have been calculated for the medically relevant radionuclides, 184,186Re.
{"title":"Cross sections for 184,186Re radioisotopes for medical applications: A proton-induced approach","authors":"S. Hinge, P. Singh, K. Churi, M. Hemalatha","doi":"10.1016/j.nuclphysa.2025.123284","DOIUrl":"10.1016/j.nuclphysa.2025.123284","url":null,"abstract":"<div><div>The study presents calculated cross sections for proton-induced reactions on <sup>180,182,183,184,186</sup>W isotopes for the production of <sup>180,182,183,184,186</sup>Re using the TALYS-2.0 nuclear reaction code. The optical model potentials were calculated using Koning-Delaroche (KD) model for protons scattering from <sup>180,182,183,184,186</sup>W isotopes. Using the potentials, the calculated differential elastic scattering and total reaction cross sections were compared with corresponding data where available and were found to be in good agreement. Further, the calculated (p,n) reaction cross sections were calculated using nuclear level densities from both the back-shifted Fermi gas model (BFM) and the microscopic Hartree-Fock-Bogoliubov (HFB) approaches. The calculated (p,n) reaction cross sections compare well with data and TENDL-2023 for <sup>186</sup>Re for which data are available, while for the isotopes, <sup>180,182,183</sup>Re, predictions have been made. In addition, production yields have been calculated for the medically relevant radionuclides, <sup>184,186</sup>Re.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1067 ","pages":"Article 123284"},"PeriodicalIF":2.5,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145594482","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 : 2025-11-15DOI: 10.1016/j.nuclphysa.2025.123283
Halil Basaran , Gokhan Kocak , Murat Aygun
The fusion cross-sections of the 15C + 12C reaction are analyzed using the optical model at energies around the Coulomb barrier. For this objective, the present study consists of two parts. First, three different density distributions of the nucleus 15C are applied to produce the real potential of the double-folding model. Then, the fusion cross-sections are investigated using a one-dimensional potential barrier approximation at astrophysical energies with Morse-type and harmonic-oscillator potentials to make a comprehensive analysis. The theoretical results are in good agreement with the experimental data. We have concluded that the Gaussian-based density distributions are important tools for fusion cross-section calculations with neutron-rich nuclei.
{"title":"Effect of different density distributions and one-dimensional potential barrier for 15C + 12C fusion reactions at astrophysical energies","authors":"Halil Basaran , Gokhan Kocak , Murat Aygun","doi":"10.1016/j.nuclphysa.2025.123283","DOIUrl":"10.1016/j.nuclphysa.2025.123283","url":null,"abstract":"<div><div>The fusion cross-sections of the <sup>15</sup>C + <sup>12</sup>C reaction are analyzed using the optical model at energies around the Coulomb barrier. For this objective, the present study consists of two parts. First, three different density distributions of the nucleus <sup>15</sup>C are applied to produce the real potential of the double-folding model. Then, the fusion cross-sections are investigated using a one-dimensional potential barrier approximation at astrophysical energies with Morse-type and harmonic-oscillator potentials to make a comprehensive analysis. The theoretical results are in good agreement with the experimental data. We have concluded that the Gaussian-based density distributions are important tools for fusion cross-section calculations with neutron-rich nuclei.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1066 ","pages":"Article 123283"},"PeriodicalIF":2.5,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614996","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 : 2025-11-10DOI: 10.1016/j.nuclphysa.2025.123272
M. Kamil , S. Triambak , G.C. Ball , V. Bildstein , C. Burbadge , A. Diaz Varela , T. Faestermann , P.E. Garrett , R. Hertenberger , K.G. Leach , F. Ghazi Moradi , N.J. Mukwevho , B.M. Rebeiro , M. Scheck , H.-F. Wirth
The 137Ba(3He, α) neutron removal reaction was used to investigate nuclear states in 136Ba, relevant for the neutrinoless double beta decay (0νββ) of 136Xe. Preliminary values of spectroscopic factors are reported. A quenching of the measured cross sections is observed, which appears to be consistent with previous results from (e, e′p) and other single-nucleon transfer reactions.
用137Ba（3He, α）中子去除反应研究了136Ba中与136Xe无中微子双β衰变（0νββ）有关的核态。报道了光谱因子的初步值。观察到测量截面的猝灭，这似乎与先前（e, e 'p）和其他单核子转移反应的结果一致。
{"title":"Spectroscopic investigation of states in 136Ba via the 137Ba(3He, α) reaction","authors":"M. Kamil , S. Triambak , G.C. Ball , V. Bildstein , C. Burbadge , A. Diaz Varela , T. Faestermann , P.E. Garrett , R. Hertenberger , K.G. Leach , F. Ghazi Moradi , N.J. Mukwevho , B.M. Rebeiro , M. Scheck , H.-F. Wirth","doi":"10.1016/j.nuclphysa.2025.123272","DOIUrl":"10.1016/j.nuclphysa.2025.123272","url":null,"abstract":"<div><div>The <sup>137</sup>Ba(<sup>3</sup>He, <em>α</em>) neutron removal reaction was used to investigate nuclear states in <sup>136</sup>Ba, relevant for the neutrinoless double beta decay (0<em>νββ</em>) of <sup>136</sup>Xe. Preliminary values of spectroscopic factors are reported. A quenching of the measured cross sections is observed, which appears to be consistent with previous results from (<em>e, e</em>′<em>p</em>) and other single-nucleon transfer reactions.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1066 ","pages":"Article 123272"},"PeriodicalIF":2.5,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569570","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 : 2025-11-04DOI: 10.1016/j.nuclphysa.2025.123273
C. Fougères , O. Roig , M. Pottier , L. Gaudefroy , V. Méot
A spectroscopic study of the isomeric state in 209Pb has been performed to shed more light on the octupole phonons near the doubly-magic nucleus 208Pb. Populated by neutron-transfer reactions 208Pb(d, p)209Pb*, the de-exciting nuclei of interest were measured with the SFγNCS array, a versatile set-up comprising a silicon telescope and 60 NaI(Tl) detectors. Determined with particle-γ-ray coincidences, the branching ratio and multipolarity of the aimed γ-ray transition of the state in 209Pb were found to be consistent with the literature. The state lifetime was precisely measured with the delayed coincidence method. The resulting reduced transition probability W.u. is an order of magnitude more precise than previously reported. An analysis in terms of the particle-octupole-vibration coupling model led to a reevaluation of the neutron E3 effective charge. This new experimental result on the lifetime of the octupole state in 209Pb should help future investigations to constrain the nature of states in 207,208,209Pb.
{"title":"A new lifetime measurement of the 15/21− octupole state in 209Pb","authors":"C. Fougères , O. Roig , M. Pottier , L. Gaudefroy , V. Méot","doi":"10.1016/j.nuclphysa.2025.123273","DOIUrl":"10.1016/j.nuclphysa.2025.123273","url":null,"abstract":"<div><div>A spectroscopic study of the <span><math><mrow><mn>15</mn><mo>/</mo><msubsup><mn>2</mn><mn>1</mn><mo>−</mo></msubsup></mrow></math></span> isomeric state in <sup>209</sup>Pb has been performed to shed more light on the octupole phonons near the doubly-magic nucleus <sup>208</sup>Pb. Populated by neutron-transfer reactions <sup>208</sup>Pb(<em>d, p</em>)<sup>209</sup>Pb*, the de-exciting nuclei of interest were measured with the SF<em>γ</em>NCS array, a versatile set-up comprising a silicon telescope and 60 NaI(Tl) detectors. Determined with particle-<em>γ</em>-ray coincidences, the branching ratio and multipolarity of the aimed <em>γ</em>-ray transition of the <span><math><mrow><mn>15</mn><mo>/</mo><msubsup><mn>2</mn><mn>1</mn><mo>−</mo></msubsup></mrow></math></span> state in <sup>209</sup>Pb were found to be consistent with the literature. The state lifetime was precisely measured with the delayed coincidence method. The resulting reduced transition probability <span><math><mrow><mi>B</mi><mrow><mo>(</mo><mi>E</mi><mn>3</mn><mo>,</mo><mn>15</mn><mo>/</mo><msubsup><mn>2</mn><mn>1</mn><mo>−</mo></msubsup><mo>→</mo><mn>9</mn><mo>/</mo><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup><mo>)</mo></mrow><mo>=</mo><mn>24.2</mn><mrow><mo>(</mo><mn>4</mn><mo>)</mo></mrow></mrow></math></span> W.u. is an order of magnitude more precise than previously reported. An analysis in terms of the particle-octupole-vibration coupling model led to a reevaluation of the neutron <em>E</em>3 effective charge. This new experimental result on the lifetime of the <span><math><mrow><mn>15</mn><mo>/</mo><msubsup><mn>2</mn><mn>1</mn><mo>−</mo></msubsup></mrow></math></span> octupole state in <sup>209</sup>Pb should help future investigations to constrain the nature of states in <sup>207,208,209</sup>Pb.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1066 ","pages":"Article 123273"},"PeriodicalIF":2.5,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517834","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 : 2025-10-31DOI: 10.1016/j.nuclphysa.2025.123265
A. Karmakar , P. Datta , S.S. Nayak , Soumik Bhattacharya , Suchorita Paul , Snigdha Pal , S. Bhattacharyya , G. Mukherjee , S. Basu , S. Chakraborty , S. Panwar , Pankaj K. Giri , R. Raut , S.S. Ghugre , R. Palit , Sajad Ali , W. Shaikh , S. Chattopadhyay
The high spin level structures of Mo have been studied through discrete -ray spectroscopy. This study extends the existing band structures to higher spins and also shows two new E3 transitions. The spin and parity of most energy levels have been uniquely established from the present dataset. An extensive comparison with , an octupole-deformed nucleus in the mass 100 region, reveals similarities that suggest the presence of octupole collectivity in . This observation is relevant in establishing A 100 as another valley of octupole collectivity.
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