Pub Date : 2025-02-15DOI: 10.1016/j.nuclphysa.2025.123037
Salvatore Simone Perrotta, Cole Davis Pruitt, Oliver C. Gorton, Jutta E. Escher
Optical-model potentials (OMPs) are critical ingredients for basic and applied nuclear physics. Present-day computational capabilities allow us to generate data-driven nucleon-nucleus OMPs that are non-local and exactly dispersive (as theoretically required to be), include statistically-sound uncertainty quantification, and are trained on both scattering and bound-state data from a wide area of the nuclear chart. Combined together, these features allow for significant improvement in fidelity and extrapolative power of the model. Here, we present preliminary work toward the development and training of such an OMP. The capability of the model to describe data at this first stage is encouraging.
{"title":"Towards next-generation optical potentials for nuclear reactions and structure calculations","authors":"Salvatore Simone Perrotta, Cole Davis Pruitt, Oliver C. Gorton, Jutta E. Escher","doi":"10.1016/j.nuclphysa.2025.123037","DOIUrl":"10.1016/j.nuclphysa.2025.123037","url":null,"abstract":"<div><div>Optical-model potentials (OMPs) are critical ingredients for basic and applied nuclear physics. Present-day computational capabilities allow us to generate data-driven nucleon-nucleus OMPs that are non-local and exactly dispersive (as theoretically required to be), include statistically-sound uncertainty quantification, and are trained on both scattering and bound-state data from a wide area of the nuclear chart. Combined together, these features allow for significant improvement in fidelity and extrapolative power of the model. Here, we present preliminary work toward the development and training of such an OMP. The capability of the model to describe data at this first stage is encouraging.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1057 ","pages":"Article 123037"},"PeriodicalIF":1.7,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454163","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 : 2025-02-14DOI: 10.1016/j.nuclphysa.2025.123034
C. Özen , Y. Alhassid
Level densities are often parametrized using the back-shifted Bethe formula (BBF) for nuclei that have experimental data for s-wave neutron resonance average spacings and a complete discrete level sequence at low excitation energies. However, these parametrizations require additional modeling of the dependence of the spin-cutoff parameter on excitation energy. Here we avoid the need to model the spin distribution of level densities by using the experimental data to parametrize directly the state densities, for which the BBF does not depend on the spin-cutoff parameter. This approach allows for a local parameterization of state densities that is independent of the spin-cutoff parameter. We provide these parameters in a tabulated form for applications in nuclear reaction calculations and for testing microscopic approaches to state densities.
{"title":"Direct local parametrization of nuclear state densities using the back-shifted Bethe formula","authors":"C. Özen , Y. Alhassid","doi":"10.1016/j.nuclphysa.2025.123034","DOIUrl":"10.1016/j.nuclphysa.2025.123034","url":null,"abstract":"<div><div>Level densities are often parametrized using the back-shifted Bethe formula (BBF) for nuclei that have experimental data for s-wave neutron resonance average spacings and a complete discrete level sequence at low excitation energies. However, these parametrizations require additional modeling of the dependence of the spin-cutoff parameter on excitation energy. Here we avoid the need to model the spin distribution of level densities by using the experimental data to parametrize directly the state densities, for which the BBF does not depend on the spin-cutoff parameter. This approach allows for a local parameterization of state densities that is independent of the spin-cutoff parameter. We provide these parameters in a tabulated form for applications in nuclear reaction calculations and for testing microscopic approaches to state densities.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1058 ","pages":"Article 123034"},"PeriodicalIF":1.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552275","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 : 2025-02-14DOI: 10.1016/j.nuclphysa.2025.123041
Ali Mollaebrahimi , Paul Constantin , Timo Dickel , Daler Amanbayev , Simeon Glöckner , Emma Haettner , Debodyuti Kar , Gabriella Kripko-Koncz , Deepak Kumar , Kriti Mahajan , Israel Mardor , David Morrissey , Meetika Narang , Wolfgang R. Plaß , Amir Shrayer , Nazarena Tortorelli , Jiajun Yu , Jasmiina Ahokas , Beatriz Amorim , Samuel Ayet San Andrés , Jianwei Zhao
An exploratory experiment on Multi-Nucleon Transfer (MNT) reactions was successfully conducted at the FRS Ion Catcher setup at GSI. The experiment demonstrated the production of MNT-driven radioactive ion beams (RIBs) produced by decelerated relativistic beams. A beam of 238U ions was reacted with a 209Bi target at near-Coulomb barrier energies inside the specially modified Cryogenic Stopping Cell (CSC) for the production and thermalization of MNT products. These products were then identified using a Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS). The observation of target-like MNT fragments along the isobaric chain provided a proof-of-principle for future MNT studies with the FRS Ion Catcher setup.
{"title":"First observation of MNT isotope beams at the FRS Ion Catcher","authors":"Ali Mollaebrahimi , Paul Constantin , Timo Dickel , Daler Amanbayev , Simeon Glöckner , Emma Haettner , Debodyuti Kar , Gabriella Kripko-Koncz , Deepak Kumar , Kriti Mahajan , Israel Mardor , David Morrissey , Meetika Narang , Wolfgang R. Plaß , Amir Shrayer , Nazarena Tortorelli , Jiajun Yu , Jasmiina Ahokas , Beatriz Amorim , Samuel Ayet San Andrés , Jianwei Zhao","doi":"10.1016/j.nuclphysa.2025.123041","DOIUrl":"10.1016/j.nuclphysa.2025.123041","url":null,"abstract":"<div><div>An exploratory experiment on Multi-Nucleon Transfer (MNT) reactions was successfully conducted at the FRS Ion Catcher setup at GSI. The experiment demonstrated the production of MNT-driven radioactive ion beams (RIBs) produced by decelerated relativistic beams. A beam of <sup>238</sup>U ions was reacted with a <sup>209</sup>Bi target at near-Coulomb barrier energies inside the specially modified Cryogenic Stopping Cell (CSC) for the production and thermalization of MNT products. These products were then identified using a Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS). The observation of target-like MNT fragments along the <span><math><mi>A</mi><mo>=</mo><mn>211</mn></math></span> isobaric chain provided a proof-of-principle for future MNT studies with the FRS Ion Catcher setup.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1057 ","pages":"Article 123041"},"PeriodicalIF":1.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2025-02-14DOI: 10.1016/j.nuclphysa.2025.123042
J. Williams , G. Hackman , K. Starosta , R.S. Lubna , Priyanka Choudhary , S. Sahoo , P.C. Srivastava , C. Andreoiu , D. Annen , H. Asch , M.D.H.K.G. Badanage , G.C. Ball , M. Beuschlein , H. Bidaman , V. Bildstein , R. Coleman , A.B. Garnsworthy , B. Greaves , G. Leckenby , V. Karayonchev , Z. Yu
In the neutron-rich sd shell near the ‘island of inversion’, the evolution of the shell gap is indicated by the energies of negative-parity states which primarily arise due to single neutron excitation to higher lying orbitals across the shell gap. These negative-parity states often have high spin (due to the participation of the orbital) and are therefore preferentially populated using fusion-evaporation reactions. We have studied the intermediate energy levels of 32Si and 29Al using 12C(22Ne,2p) and 12C(22Ne,αp) reactions, identifying several negative-parity states in both nuclides.
{"title":"Cross-shell excited states in 32Si and 29Al populated using fusion-evaporation","authors":"J. Williams , G. Hackman , K. Starosta , R.S. Lubna , Priyanka Choudhary , S. Sahoo , P.C. Srivastava , C. Andreoiu , D. Annen , H. Asch , M.D.H.K.G. Badanage , G.C. Ball , M. Beuschlein , H. Bidaman , V. Bildstein , R. Coleman , A.B. Garnsworthy , B. Greaves , G. Leckenby , V. Karayonchev , Z. Yu","doi":"10.1016/j.nuclphysa.2025.123042","DOIUrl":"10.1016/j.nuclphysa.2025.123042","url":null,"abstract":"<div><div>In the neutron-rich <em>sd</em> shell near the <span><math><mi>N</mi><mo>=</mo><mn>20</mn></math></span> ‘island of inversion’, the evolution of the <span><math><mi>N</mi><mo>=</mo><mn>20</mn></math></span> shell gap is indicated by the energies of negative-parity states which primarily arise due to single neutron excitation to higher lying orbitals across the shell gap. These negative-parity states often have high spin (due to the participation of the <span><math><mn>0</mn><msub><mrow><mi>f</mi></mrow><mrow><mn>7</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> orbital) and are therefore preferentially populated using fusion-evaporation reactions. We have studied the intermediate energy levels of <sup>32</sup>Si and <sup>29</sup>Al using <sup>12</sup>C(<sup>22</sup>Ne,2p) and <sup>12</sup>C(<sup>22</sup>Ne,<em>α</em>p) reactions, identifying several negative-parity states in both nuclides.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1057 ","pages":"Article 123042"},"PeriodicalIF":1.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143427632","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 : 2025-02-14DOI: 10.1016/j.nuclphysa.2025.123038
A.B. McIntosh , A.D. Abbott , M.Q. Sorensen , K. Hagel , A. Couture , J. Gauthier , S. Ota , A. Alvarez , S. Balakrishnan , R. Ghimire , M. Grinder , I. Jeanis , T. King , L.A. McIntosh , S. Mosby , S.D. Pain , C. Prokop , A. Ratkiewicz , S. Regener , A. Rodriguez-Manso , S.J. Yennello
Accurate neutron capture predictions are needed in fundamental and applied science. Empirical models are constrained largely for stable nuclei, but predictions far from stability are needed. Neutron transfer in (d, p) reactions in inverse kinematics with rare isotope beams offers a means to access key aspects of the capture process. To this end, the detector array for photons, protons, and exotic residues (DAPPER) has been designed, built, tested, and used for measurement at Texas A&M University.
{"title":"Development of the detector array for photons, protons, and exotic residues","authors":"A.B. McIntosh , A.D. Abbott , M.Q. Sorensen , K. Hagel , A. Couture , J. Gauthier , S. Ota , A. Alvarez , S. Balakrishnan , R. Ghimire , M. Grinder , I. Jeanis , T. King , L.A. McIntosh , S. Mosby , S.D. Pain , C. Prokop , A. Ratkiewicz , S. Regener , A. Rodriguez-Manso , S.J. Yennello","doi":"10.1016/j.nuclphysa.2025.123038","DOIUrl":"10.1016/j.nuclphysa.2025.123038","url":null,"abstract":"<div><div>Accurate neutron capture predictions are needed in fundamental and applied science. Empirical models are constrained largely for stable nuclei, but predictions far from stability are needed. Neutron transfer in (d, p) reactions in inverse kinematics with rare isotope beams offers a means to access key aspects of the capture process. To this end, the detector array for photons, protons, and exotic residues (DAPPER) has been designed, built, tested, and used for measurement at Texas A&M University.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1057 ","pages":"Article 123038"},"PeriodicalIF":1.7,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143445542","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 : 2025-02-13DOI: 10.1016/j.nuclphysa.2025.123033
Ramutis Kazys Kalinauskas , Augustinas Stepšys , Darius Germanas , Saulius Mickevičius
We present a new approach for the Talmi-Moshinsky transformation representation in the harmonic oscillator basis. We utilize the SU(3) scheme for calculation of harmonic oscillator brackets. Using this scheme we obtain the explicit relations for numeric evaluation and present a computational approach.
{"title":"Calculation of harmonic oscillator brackets in SU(3) basis","authors":"Ramutis Kazys Kalinauskas , Augustinas Stepšys , Darius Germanas , Saulius Mickevičius","doi":"10.1016/j.nuclphysa.2025.123033","DOIUrl":"10.1016/j.nuclphysa.2025.123033","url":null,"abstract":"<div><div>We present a new approach for the Talmi-Moshinsky transformation representation in the harmonic oscillator basis. We utilize the SU(3) scheme for calculation of harmonic oscillator brackets. Using this scheme we obtain the explicit relations for numeric evaluation and present a computational approach.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1056 ","pages":"Article 123033"},"PeriodicalIF":1.7,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143422742","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 : 2025-02-11DOI: 10.1016/j.nuclphysa.2025.123031
Ashok Kumar Mondal, Sathi Sharma
In this work, we re-evaluate the reaction rate for the 26Si(p,γ)27P process, motivated by discrepancies in previous studies regarding key parameters such as , , ωγ, and the S - factor at zero energy, S(0). Using the NuShellX code with the newly developed USDCm interaction [20], we performed shell model calculations to reproduce energy levels and calculate spectroscopic factors for various states. The gamma width () values for the 3/2+ and 5/2+ states were determined using shell model calculations. Additionally, we employed the WSPOT code to analyze scattering cross-sections and phase shifts to compute the proton width () values. After that, we have calculated the resonance strength (ωγ) values for 3/2+ and 5/2+ states respectively. Here, we have utilized the RADCAP code to calculate the S - factor at zero energy, S(0). Finally, we computed the reaction rates across a temperature range of 0.1 - 2 GK. Our results provide a refined understanding of the 26Si(p,γ)27P reaction rate, addressing inconsistencies in previous studies.
{"title":"Re-evaluation of the 26Si(p,γ)27P astrophysical reaction rate","authors":"Ashok Kumar Mondal, Sathi Sharma","doi":"10.1016/j.nuclphysa.2025.123031","DOIUrl":"10.1016/j.nuclphysa.2025.123031","url":null,"abstract":"<div><div>In this work, we re-evaluate the reaction rate for the <sup>26</sup>Si(p,<em>γ</em>)<sup>27</sup>P process, motivated by discrepancies in previous studies regarding key parameters such as <span><math><msub><mrow><mi>Γ</mi></mrow><mrow><mi>γ</mi></mrow></msub></math></span>, <span><math><msub><mrow><mi>Γ</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, <em>ωγ</em>, and the S - factor at zero energy, S(0). Using the NuShellX code with the newly developed USDCm interaction <span><span>[20]</span></span>, we performed shell model calculations to reproduce energy levels and calculate spectroscopic factors for various states. The gamma width (<span><math><msub><mrow><mi>Γ</mi></mrow><mrow><mi>γ</mi></mrow></msub></math></span>) values for the 3/2<sup>+</sup> and 5/2<sup>+</sup> states were determined using shell model calculations. Additionally, we employed the WSPOT code to analyze scattering cross-sections and phase shifts to compute the proton width (<span><math><msub><mrow><mi>Γ</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>) values. After that, we have calculated the resonance strength (<em>ωγ</em>) values for 3/2<sup>+</sup> and 5/2<sup>+</sup> states respectively. Here, we have utilized the RADCAP code to calculate the S - factor at zero energy, S(0). Finally, we computed the reaction rates across a temperature range of 0.1 - 2 GK. Our results provide a refined understanding of the <sup>26</sup>Si(p,<em>γ</em>)<sup>27</sup>P reaction rate, addressing inconsistencies in previous studies.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1056 ","pages":"Article 123031"},"PeriodicalIF":1.7,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395325","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 : 2025-02-03DOI: 10.1016/j.nuclphysa.2025.123024
A. Hannaman , B. Harvey , K. Hagel , A.B. McIntosh , A. Abbott , L. Bills , A. Fentress , J. Gauthier , T. Hankins , Y.-W. Lui , L.A. McIntosh , S. Regener , R. Rider , S. Schultz , M.Q. Sorensen , J. Tobar , Z. Tobin , S. Yennello
Ground state nuclei usually have compact geometries. However, there have been theoretical predictions that excited nuclei can take on more extended shapes such as toroids or bubbles. There have been many attempts to identify signatures of such shapes in experimental data. One signature, both predicted by theory and sought by experimental data, is narrow resonances at high excitation energy in peripheral intermediate-energy heavy-ion collisions. Potential evidence for toroidal states was reported in the alpha particle disassembly of 28Si after collision with a 12C target at 35 MeV/nucleon. The prior work was limited by angular resolution and statistical uncertainties. The present work aims to measure the excitation energy distribution for these disassembly events with improved angular resolution and reduced statistical uncertainty using the Forward Array Using Silicon Technology (FAUST). FAUST is equipped with resistive dual-axis duo-lateral (DADL) position-sensitive silicon detectors capable of sub-millimeter position resolution. The measured excitation energy distributions of 7-α disassembly events showed no strong evidence for highly excited states at the cross section and widths suggested by previous experiment. A statistical likelihood analysis was performed to provide an upper limit to toroidal high-spin isomer cross section, as evidenced by this observable, as a function of the excitation energy and width of potential states.
{"title":"Upper bounds on the production cross section of toroidally deformed nuclei","authors":"A. Hannaman , B. Harvey , K. Hagel , A.B. McIntosh , A. Abbott , L. Bills , A. Fentress , J. Gauthier , T. Hankins , Y.-W. Lui , L.A. McIntosh , S. Regener , R. Rider , S. Schultz , M.Q. Sorensen , J. Tobar , Z. Tobin , S. Yennello","doi":"10.1016/j.nuclphysa.2025.123024","DOIUrl":"10.1016/j.nuclphysa.2025.123024","url":null,"abstract":"<div><div>Ground state nuclei usually have compact geometries. However, there have been theoretical predictions that excited nuclei can take on more extended shapes such as toroids or bubbles. There have been many attempts to identify signatures of such shapes in experimental data. One signature, both predicted by theory and sought by experimental data, is narrow resonances at high excitation energy in peripheral intermediate-energy heavy-ion collisions. Potential evidence for toroidal states was reported in the alpha particle disassembly of <sup>28</sup>Si after collision with a <sup>12</sup>C target at 35 MeV/nucleon. The prior work was limited by angular resolution and statistical uncertainties. The present work aims to measure the excitation energy distribution for these disassembly events with improved angular resolution and reduced statistical uncertainty using the Forward Array Using Silicon Technology (FAUST). FAUST is equipped with resistive dual-axis duo-lateral (DADL) position-sensitive silicon detectors capable of sub-millimeter position resolution. The measured excitation energy distributions of 7-<em>α</em> disassembly events showed no strong evidence for highly excited states at the cross section and widths suggested by previous experiment. A statistical likelihood analysis was performed to provide an upper limit to toroidal high-spin isomer cross section, as evidenced by this observable, as a function of the excitation energy and width of potential states.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1056 ","pages":"Article 123024"},"PeriodicalIF":1.7,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387320","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 : 2025-01-27DOI: 10.1016/j.nuclphysa.2025.123022
L. Ponnath , T. Aumann , C.A. Bertulani , R. Gernhäuser , T. Almusidi , H. Alvarez-Pol , L. Atar , L. Atkins , Y. Ayyad , J. Benlliure , K. Boretzky , M.J.G. Borge , L.T. Bott , G. Bruni , B. Brückner , P. Cabanelas , C. Caesar , E. Casarejos , J. Cederkall , A. Corsi , F. Wamers
The R3B (Reactions with Relativistic Radioactive Beams) experiment as a major instrument of the NUSTAR collaboration for the research facility FAIR in Darmstadt is designed for kinematically complete studies of reactions with high-energy radioactive beams. Part of the broad physics program of R3B is to constrain the asymmetry term in the nuclear equation-of-state and hence improve the description of highly asymmetric nuclear matter (e.g., in neutron stars). For a precise determination of the neutron-skin thickness – an observable which is directly correlated with the symmetry energy in theoretical calculations – by measuring absolute fragmentation cross sections, it is essential to quantify the uncertainty and challenge the reaction model under stable conditions. During the successful FAIR Phase-0 campaign of R3B, we precisely measured the energy dependence of total interaction cross sections in 12C+12C collisions, for a direct comparison with calculations based on the eikonal reaction theory.
{"title":"Precise measurement of nuclear interaction cross sections towards neutron-skin determination with R3B","authors":"L. Ponnath , T. Aumann , C.A. Bertulani , R. Gernhäuser , T. Almusidi , H. Alvarez-Pol , L. Atar , L. Atkins , Y. Ayyad , J. Benlliure , K. Boretzky , M.J.G. Borge , L.T. Bott , G. Bruni , B. Brückner , P. Cabanelas , C. Caesar , E. Casarejos , J. Cederkall , A. Corsi , F. Wamers","doi":"10.1016/j.nuclphysa.2025.123022","DOIUrl":"10.1016/j.nuclphysa.2025.123022","url":null,"abstract":"<div><div>The R<sup>3</sup>B (Reactions with Relativistic Radioactive Beams) experiment as a major instrument of the NUSTAR collaboration for the research facility FAIR in Darmstadt is designed for kinematically complete studies of reactions with high-energy radioactive beams. Part of the broad physics program of R<sup>3</sup>B is to constrain the asymmetry term in the nuclear equation-of-state and hence improve the description of highly asymmetric nuclear matter (e.g., in neutron stars). For a precise determination of the neutron-skin thickness – an observable which is directly correlated with the symmetry energy in theoretical calculations – by measuring absolute fragmentation cross sections, it is essential to quantify the uncertainty and challenge the reaction model under stable conditions. During the successful FAIR Phase-0 campaign of R<sup>3</sup>B, we precisely measured the energy dependence of total interaction cross sections in <sup>12</sup>C+<sup>12</sup>C collisions, for a direct comparison with calculations based on the eikonal reaction theory.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1056 ","pages":"Article 123022"},"PeriodicalIF":1.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143211112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2025-01-24DOI: 10.1016/j.nuclphysa.2025.123023
S. Pigliapoco , M.L. Cortés , F. Recchia , S.M. Lenzi , M.A. Bentley , P. Doornenbal , A. Jungclaus , K. Wimmer , L. Zago , D. Rudolph , F. Browne , T. Koiwai , H. Sakurai , T. Arici , A. Fernández , J.A. Tostevin , N. Imai , N. Kitamura , B. Longfellow , R. Lozeva , R. Yajzey
This study reports the status of the first in-beam γ-ray spectroscopic study of excited states in the exotic neutron-deficient -3/2 nucleus 55Cu. The nucleus was produced via knock-out reactions at the Radioactive Isotope Beam Factory, located at the RIKEN-Nishina Center. Several γ-ray transitions were detected using the DALI2+γ-ray detector array. The comparison with isobaric analogue states in the mirror nucleus 55Fe will provide valuable insights into isospin-non-conserving effects beyond nuclear stability. The proton occupation of the 1 orbital is expected to play a significant effect on the orbital's charge radius due to the isovector monopole polarizability, which can be linked to the measured mirror energy differences.
{"title":"Isospin symmetry investigation of the proton-unbound nucleus T = 3/2 55Cu","authors":"S. Pigliapoco , M.L. Cortés , F. Recchia , S.M. Lenzi , M.A. Bentley , P. Doornenbal , A. Jungclaus , K. Wimmer , L. Zago , D. Rudolph , F. Browne , T. Koiwai , H. Sakurai , T. Arici , A. Fernández , J.A. Tostevin , N. Imai , N. Kitamura , B. Longfellow , R. Lozeva , R. Yajzey","doi":"10.1016/j.nuclphysa.2025.123023","DOIUrl":"10.1016/j.nuclphysa.2025.123023","url":null,"abstract":"<div><div>This study reports the status of the first in-beam <em>γ</em>-ray spectroscopic study of excited states in the exotic neutron-deficient <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>z</mi></mrow></msub><mo>=</mo></math></span>-3/2 nucleus <sup>55</sup>Cu. The nucleus was produced via knock-out reactions at the Radioactive Isotope Beam Factory, located at the RIKEN-Nishina Center. Several <em>γ</em>-ray transitions were detected using the DALI2<sup>+</sup> <em>γ</em>-ray detector array. The comparison with isobaric analogue states in the mirror nucleus <sup>55</sup>Fe will provide valuable insights into isospin-non-conserving effects beyond nuclear stability. The proton occupation of the 1<span><math><msub><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> orbital is expected to play a significant effect on the orbital's charge radius due to the isovector monopole polarizability, which can be linked to the measured mirror energy differences.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1056 ","pages":"Article 123023"},"PeriodicalIF":1.7,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
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