{"title":"Stability of quark matter affected by the surface tension in a strong magnetic field","authors":"Yu-Ying He, Xin-Jian Wen","doi":"10.1140/epja/s10050-025-01544-2","DOIUrl":"10.1140/epja/s10050-025-01544-2","url":null,"abstract":"<div><p>The surface tension of quark matter in a strong magnetic field is investigated using a geometric approach. The interface between the hadronic phase and the quark phase is determined by the Maxwell construction of the first-order transition. When surface tension is included, the free energy per baryon is no longer a monotonic function of the chemical potential. Specifically, for smaller droplets, a larger chemical potential is required to achieve a stable phase. Moreover, we find that the surface tension does not increase monotonically with the magnetic field. Finally, it is shown that stable quark matter, both with and without surface tension, can exist at a specific magnetic field strength, which would provide favorable conditions for the experimental production of quark matter.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143902738","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}
Z.-Q. Yao, Y.-Z. Xu, D. Binosi, Z.-F. Cui, M. Ding, K. Raya, C. D. Roberts, J. Rodríguez-Quintero, S. M. Schmidt
{"title":"Nucleon gravitational form factors","authors":"Z.-Q. Yao, Y.-Z. Xu, D. Binosi, Z.-F. Cui, M. Ding, K. Raya, C. D. Roberts, J. Rodríguez-Quintero, S. M. Schmidt","doi":"10.1140/epja/s10050-025-01557-x","DOIUrl":"10.1140/epja/s10050-025-01557-x","url":null,"abstract":"<div><p>A symmetry-preserving analysis of strong interaction quantum field equations is used to complete a unified treatment of pion, kaon, and nucleon electromagnetic and gravitational form factors. Findings include a demonstration that the pion near-core pressure is roughly twice that in the proton, so both are significantly greater than that of a neutron star; parton species separations of the nucleon’s three gravitational form factors, in which, <i>inter alia</i>, the glue-to-quark ratio for each form factor is seen to take the same constant value, independent of momentum transfer; and a determination of proton radii orderings, with the mechanical (normal force) radius being less than the mass-energy radius, which is less than the proton charge radius. This body of predictions should prove useful in an era of experiments that will enable them to be tested.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 5","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01557-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900735","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}
{"title":"Generalized parton distributions for low-lying octet baryons with non-zero skewness","authors":"Navpreet Kaur, Harleen Dahiya","doi":"10.1140/epja/s10050-025-01565-x","DOIUrl":"10.1140/epja/s10050-025-01565-x","url":null,"abstract":"<div><p>We have performed the structural analysis of low-lying octet baryon members by assuming charge-isospin symmetry among quark flavors in transverse and longitudinal space. Using the light-cone spectator diquark model, we have investigated the electromagnetic form factors of the octet baryons and have compared them with the available data. A comparative analysis of PDFs and generalized parton distributions (GPDs) for non-zero skewness among octet baryons has also been demonstrated. Fourier transform of the deeply virtual Compton scattering amplitude with respect to skewness has been further applied to study the diffraction patterns in the boost-invariant longitudinal position space.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883587","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}
{"title":"Deciphering spin-parity assignments of nuclear levels","authors":"Christian Iliadis","doi":"10.1140/epja/s10050-025-01569-7","DOIUrl":"10.1140/epja/s10050-025-01569-7","url":null,"abstract":"<div><p>Spin-parity assignments of nuclear levels are critical for understanding nuclear structure and reactions. However, inconsistent notation conventions and ambiguous reporting in research papers often lead to confusion and misinterpretations. This paper examines the policies of the Evaluated Nuclear Structure Data File (ENSDF) and the evaluations by Endt and collaborators, highlighting key differences in their approaches to spin-parity notation. Sources of confusion are identified, including ambiguous use of strong and weak arguments and the conflation of new experimental results with prior constraints. Recommendations are provided to improve clarity and consistency in reporting spin-parity assignments, emphasizing the need for explicit notation conventions, clear differentiation of argument strengths, community education, and separate reporting of new findings. These steps aim to enhance the accuracy and utility of nuclear data for both researchers and evaluators.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883743","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}
{"title":"Machine learning based study of collective quadrupole–octupole excitations","authors":"Hadi Sobhani, Yan-An Luo","doi":"10.1140/epja/s10050-025-01564-y","DOIUrl":"10.1140/epja/s10050-025-01564-y","url":null,"abstract":"<div><p>We use the collective quadrupole–octupole model of axial symmetric shapes to study excited states in different Th and Ra isotopes. In this model, we use one of the most commonly used potentials in nuclear physics: Woods–Saxon potential. Extending this model based on the potential suggested is able to describe excited states due to quadrupole–octupole deformations satisfactorily. In this work, the necessary Hamiltonian is diagonalized in suitable bases to yield states of the candidate nuclei. This procedure also necessitates optimization, which is done using machine learning methods for each isotope. The findings and outcomes are carefully examined and contrasted with experimental values.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883745","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}
Fanglei Zou, Xiaojun Sun, Jingshang Zhang, Xiaodong Sun, Xi Tao, Ruirui Xu, Kang Xing, Yongli Jin
{"title":"Effects of energy levels on the double-differential cross sections for (n + ^{13})C reaction below 20 MeV","authors":"Fanglei Zou, Xiaojun Sun, Jingshang Zhang, Xiaodong Sun, Xi Tao, Ruirui Xu, Kang Xing, Yongli Jin","doi":"10.1140/epja/s10050-025-01556-y","DOIUrl":"10.1140/epja/s10050-025-01556-y","url":null,"abstract":"<div><p>The nuclear data of <span>(n + ^{13})</span>C reaction are very important in describing the evolution of nuclear astrophysics, understanding the cluster structure of light nuclei, and producting the radiocarbon. Based on the unified Hauser-Feshbach and exciton model, a statistical theory of light nucleus reaction (STLN) is improved to describe the effects of energy levels on the double-differential cross sections of neutron and charged particles for <span>(n + ^{13})</span>C reaction. The individual contributions of every energy level of the target and different residual nuclei have been analysed. The calculated results agree well with all of the existing experimental double-differential cross sections of outgoing neutron. And the theoretical analysis provides an evidence for the existence of the possible levels of <span>(^{13})</span>C. The results also indicate that the contributions of the direct inelastic scattering derived from DWBA theory and the three-body breakup reaction should be considered. Especially, the contributions of (<i>n</i>, 2<i>n</i>) channel of the 6-th energy level of <span>(^{13})</span>C have been considered. The doubt regarding the significant discrepancies observed near 3-MeV exit energy range for two closely spaced incident energies of 8.09 MeV and 8.24 MeV has been clarified. Furthermore, the total double-differential cross sections of outgoing proton, deuteron, triton, and <span>(alpha )</span> can be self-consistently predicted at arbitrary outgoing angles and incident energies for <span>(n+^{13}text {C})</span> reaction.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879632","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}
{"title":"Beta-delayed particle emission and collective rotations","authors":"K. Riisager, E. A. M. Jensen, A. S. Jensen","doi":"10.1140/epja/s10050-025-01550-4","DOIUrl":"10.1140/epja/s10050-025-01550-4","url":null,"abstract":"<div><p>Beta-delayed proton emission in the lower half of the sd-shell will involve deformed nuclei. We derive the normalized matrix element connecting emission of one particle from an initial rotational nuclear state to another final rotating state, and we extract selection rules involving the <i>K</i> quantum number. The initial state is approximated as having a core identical to the final nuclear state. The formalism is then directly applicable to <span>(beta ^+)</span>-delayed proton decays of even-<i>Z</i>, odd-<i>N</i> nuclei or <span>(beta ^-)</span>-delayed neutron decays of odd-<i>Z</i>, even <i>N</i> nuclei. These beta-decay results are compared to the outcomes of possible transfer reactions. As an example the beta-delayed proton emission of <span>(^{21})</span>Mg is considered, where new structure information is obtained and quantum numbers assigned to several states in <span>(^{21})</span>Na.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01550-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879629","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}
P. Mohr, Zs. Fülöp, Gy. Gyürky, Z. Halász, G. G. Kiss, S. R. Kovács, Zs. Mátyus, T. N. Szegedi, T. Szücs
{"title":"The (alpha )-nucleus potential: towards a solution of a long-standing problem","authors":"P. Mohr, Zs. Fülöp, Gy. Gyürky, Z. Halász, G. G. Kiss, S. R. Kovács, Zs. Mátyus, T. N. Szegedi, T. Szücs","doi":"10.1140/epja/s10050-025-01551-3","DOIUrl":"10.1140/epja/s10050-025-01551-3","url":null,"abstract":"<div><p>This study presents an overview over <span>(alpha )</span>-nucleus potentials which are the essential ingredient for the calculation of cross sections and astrophysical reaction rates for <span>(alpha )</span>-induced reactions on intermediate mass and heavy nuclei within the statistical model. Recent experimental data for Mo + <span>(alpha )</span> have been chosen as an example to illustrate the properties of several widely used <span>(alpha )</span>-nucleus potentials. The delicate role of the imaginary part of the potential at large radii is discussed which is the origin of the widely discrepant predictions of the different potentials at low energies far below the Coulomb barrier. The Atomki-V2 potential circumvents the complications with the imaginary part and provides very good predictions for the recent Mo + <span>(alpha )</span> data and also for most other recent reactions and is thus an excellent basis for the calculation of reaction rates. But further improvements are possible, and some ideas in this direction are given in the discussion.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01551-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883744","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}
{"title":"Perturbative quantum Monte Carlo calculation with high-fidelity nuclear forces","authors":"Jun Liu, Teng Wang, Bing-Nan Lu","doi":"10.1140/epja/s10050-025-01568-8","DOIUrl":"10.1140/epja/s10050-025-01568-8","url":null,"abstract":"<div><p>Quantum Monte Carlo (QMC) is a family of powerful tools for addressing quantum many-body problems. However, its applications are often plagued by the fermionic sign problem. A promising strategy is to simulate an interaction without sign problem as the zeroth order and treat the other pieces as perturbations. According to this scheme, we construct precision nuclear chiral forces on the lattice and make perturbative calculations around a sign-problem-free interaction respecting the Wigner-SU4 symmetry. We employ the recently developed perturbative QMC (ptQMC) method to calculate the perturbative energies up to the second order. This work presents the first ptQMC calculations for two-body next-to-next-to-next-to leading order (<span>(hbox {N}^3)</span>LO) chiral forces and elucidates how the hierarchical nature of the chiral interactions helps organize and simplify the ptQMC calculations. We benchmark the algorithm for the deuteron, where exact solutions serve as rigorous reference points. We also reproduce the famous Tjon line by correlating the perturbative <span>(^{4})</span>He binding energies with the non-perturbative <span>(^{3})</span>H binding energies. These comprehensive demonstrations underscore the efficacy of ptQMC in resolving high-fidelity nuclear interactions, establishing its potential as a robust tool for <i>ab initio</i> nuclear structure studies.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 4","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875406","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}