The European Physical Journal A最新文献

{"title":"The CERN n_TOF NEAR station for astrophysics- and application-related neutron activation measurements","authors":"The n_TOF Collaboration","doi":"10.1140/epja/s10050-025-01674-7","DOIUrl":"10.1140/epja/s10050-025-01674-7","url":null,"abstract":"<div><p>A new experimental area, the NEAR station, has recently been built at the CERN n_TOF facility, at a short distance from the spallation target (3 m). The new area, characterized by a neutron beam of very high flux, has been designed with the purpose of performing activation measurements of interest for astrophysics and various applications. The beam is transported from the spallation target to the NEAR station through a hole in the shielding wall of the target, inside which a collimator is inserted. The new area is complemented with a <span>(gamma )</span>-ray spectroscopy laboratory, the GEAR station, equipped with a high-efficiency HPGe detector, for the measurement of the activity resulting from irradiation of a sample in the NEAR station. The use of a moderator/filter assembly is envisaged, in order to produce a neutron beam with quasi-Maxwellian energy distribution, of different thermal energies, necessary for the determination of Maxwellian Averaged Cross Sections of astrophysical interest. A new fast-cycling activation technique is also being investigated for measurements of reactions leading to isotopes of very short half life.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01674-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110453","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":"Nonlocal (N-alpha ) potential","authors":"M. I. Jaghoub,&nbsp;T. Aqel","doi":"10.1140/epja/s10050-025-01695-2","DOIUrl":"10.1140/epja/s10050-025-01695-2","url":null,"abstract":"<div><p>We used a nonlocal potential to account explicitly for nonlocalities in the <span>(N-alpha )</span> scattering process. By fitting elastic <span>(N-alpha )</span> angular distributions, over the energy range <span>(0.84 - 20.97)</span> MeV, we determined individual sets of nonlocal potential parameters and two global sets of fixed parameters one for <span>(n-alpha )</span> and the other for <span>(p-alpha )</span> elastic scattering. Our nonlocal potential model reproduced the elastic angular distributions for <span>(N-alpha )</span> and the total elastic cross section for <span>(n-alpha )</span> well. In addition, we calculated the nonlocal potential phase shifts corresponding to neutron and proton scattering off alpha particles. Our determined phase shifts are in good agreement with the experimental values. In addition, our nonlocal parameters reproduced the position of the <span>(P3/2^-)</span> resonance for the <span>(n-alpha )</span> and <span>(p-alpha )</span> scattering processes well. Accounting explicitly for nonlocalities in the <span>(N-alpha )</span> interactions can benefit studies that consider the <span>(t(d,N)alpha )</span> fusion reactions. The <span>(t(d,n)alpha )</span> reaction is important for its 17.6 MeV energy yield per fusion reaction, for its carbon-free energy production. The less prominent reaction that leads to bremsstrahlung <span>(gamma )</span> radiation is important as it provides real-time diagnostics regarding the fusion reaction rate.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110452","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":"Hydrodynamic study on the evolution of magnetized viscous QGP in the transverse plane","authors":"M. Karimabadi,&nbsp;A. F. Kord,&nbsp;B. Azadegan","doi":"10.1140/epja/s10050-025-01676-5","DOIUrl":"10.1140/epja/s10050-025-01676-5","url":null,"abstract":"<div><p>This study explores the evolution of magnetized quark-gluon plasma (QGP) within the framework of relativistic magnetohydrodynamics (MHD), with a focus on understanding its temporal and spatial dynamics under the influence of intense magnetic fields. We employ a second-order viscous corrections to investigate the QGP’s evolution, where the plasma is subjected to a magnetic field generated in the early stages of relativistic heavy-ion collisions. The system is assumed to exhibit boost invariance along the longitudinal beam axis (z-coordinate) while undergoing transverse expansion. The magnetic field is modeled as a function of the proper time <span>(tau )</span> and spatial coordinates (x, y), oriented perpendicular to the direction of fluid expansion. The QGP is assumed to possess infinite electrical conductivity. We solve the coupled Maxwell and conservation equations to obtain a detailed description of the energy density, flow velocity, and magnetic field evolution in the transverse plane of the viscous magnetized plasma. Additionally, we compute the hadron spectrum emerging from the freeze-out surface and compare our results with experimental observations, providing insights into the interplay between magnetization and the hydrodynamic evolution of QGP.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145090511","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":"Beam position monitoring system based on SiC detectors","authors":"K. Piasecki,&nbsp;E. Piasecki,&nbsp;G. Colucci,&nbsp;J. Choiński,&nbsp;H. M. Jia,&nbsp;M. Kisieliński,&nbsp;M. Kowalczyk,&nbsp;C. J. Lin,&nbsp;M. Matuszewski,&nbsp;N. R. Ma,&nbsp;A. Trzcińska,&nbsp;M. Wolińska-Cichocka,&nbsp;B. Zalewski,&nbsp;L. Yang,&nbsp;H. Q. Zhang","doi":"10.1140/epja/s10050-025-01681-8","DOIUrl":"10.1140/epja/s10050-025-01681-8","url":null,"abstract":"<div><p>The simple system for beam spot position monitoring is described. It is based on the radiation-resistive SiC detectors. The visualization of the beam spot on the target is done with a dedicated BeamMon application using the ROOT environment.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01681-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073922","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":"On two nucleons near unitarity with perturbative pions","authors":"Yu-Ping Teng,&nbsp;Harald W. Grießhammer","doi":"10.1140/epja/s10050-025-01675-6","DOIUrl":"10.1140/epja/s10050-025-01675-6","url":null,"abstract":"<div><p>We explore the impact of perturbative pions on the Unitarity Expansion in the two-nucleon S-waves of Chiral Effective Field Theory at next-to-next-to leading order (<span>(textrm{N}^{2})</span>LO). Pion exchange explicitly breaks the nontrivial fixed point’s universality, i.e.  invariance of S waves under both conformal and Wigner’s combined <span>(textrm{SU}(4))</span> spin–isospin transformations. On the other hand, Unitarity explicitly breaks chiral symmetry. The two seem incompatible in their respective exact-symmetry limits. <span>({upchi }textrm{EFT})</span> with Perturbative Pions in the Unitarity Expansion resolves the apparent conflict in the Unitarity Window (phase shifts <span>(45^circ lesssim delta (k)lesssim 135^circ )</span>), i.e.  around momenta <span>(kapprox m_pi )</span> most relevant for low-energy nuclear systems. Its only LO scale is the scattering momentum; NLO adds only scattering length, effective range and non-iterated one-pion exchange (OPE); and <span>(textrm{N}^{2})</span>LO only once-iterated OPE. Agreement in the <span>({phantom {0}}^{1}textrm{S}_{0})</span> channel is very good. Apparently large discrepancies in the <span>({phantom {0}}^{3}textrm{S}_{1})</span> channel even at <span>(kapprox 100;textrm{MeV})</span> are remedied by taking at <span>(textrm{N}^{2})</span>LO only the central part of OPE. In contradistinction to the tensor part, it is identical in the <span>({phantom {0}}^{1}textrm{S}_{0})</span> and <span>({phantom {0}}^{3}textrm{S}_{1})</span> channels. Both channels then match empirical phase shifts and pole parameters well within mutually consistent quantitative theory uncertainty estimates. Pionic effects are small, even for <span>(kgtrsim m_pi )</span>. Empirical breakdown scales are consistent with <span>(overline{Lambda }_{textrm{NN}}=frac{16pi f_pi ^2}{g_A^2M}approx 300;textrm{MeV})</span>, where iterated OPE is not suppressed. We therefore conjecture: Both conformal and Wigner symmetry in the Unitarity Expansion show <i>persistence</i>, i.e.  the footprint of both combined dominates even for <span>(kgtrsim m_pi )</span> and is more relevant than chiral symmetry, so that the tensor/Wigner-<span>(textrm{SU}(4))</span> symmetry-breaking part of OPE does not enter before <span>(textrm{N}^{3})</span>LO. We also discuss the potential relevance of entanglement and possible resolution of a conflict with the strength of the tensor interaction in the large-<span>(N_C)</span> expansion.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073708","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":"Secondary bow with ripples in (^{12})C+(^{12})C rainbow scattering","authors":"S. Ohkubo,&nbsp;Y. Hirabayashi","doi":"10.1140/epja/s10050-025-01685-4","DOIUrl":"10.1140/epja/s10050-025-01685-4","url":null,"abstract":"<div><p>We report, for the first time, the emergence of a secondary bow with ripples in <span>(^{12})</span>C+<span>(^{12})</span>C nuclear rainbow scattering. This finding was achieved by studying the experimental angular distributions in <span>(^{12})</span>C+<span>(^{12})</span>C scattering at incident energies <span>(E_L)</span> = 240 and 300 MeV, utilizing an extended double-folding model. This model accurately describes all diagonal and off-diagonal coupling potentials derived from the microscopic wave functions for <span>(^{12})</span>C. Although the observed angular distributions of rainbow scattering at large angles (approaching <span>(90^circ )</span>) are complicated by the symmetrization of two identical bosonic nuclei, the Airy minimum, associated with a dynamically generated secondary bow with ripples, is clearly identified at approximately 77<span>(^circ )</span> for 240 MeV in the fall-off region of the primary nuclear rainbow. This finding, along with previous findings in the <span>(^{16})</span>O+<span>(^{12})</span>C and <span>(^{13})</span>C+<span>(^{12})</span>C systems, reinforces the concept of a secondary bow in nuclear rainbow scattering.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145062321","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":"Post-neutron fragment distributions of 233U(nth,f) and how they are influenced by model ingredients and pre-neutron fragment distributions","authors":"Anabella Tudora","doi":"10.1140/epja/s10050-025-01662-x","DOIUrl":"10.1140/epja/s10050-025-01662-x","url":null,"abstract":"<div><p>The series of investigations focused on post-neutron fragment distributions, i.e. fractional and total independent yields (Y(Z,A_p), Y(A_p)), isotonic yields of post neutron fragments (Y(N_p)), kinetic energy distributions of secondary fragments (KE_p), and the various influences on them as well as of different correlations between pre- and post-neutron fragment quantities (performed for ²³⁵U(n_th,f), ²³⁹Pu(n_th,f) and ²⁵²Cf(SF)) is ending now with a deeper investigation devoted to ²³³U(n_th,f). This has involved comprehensive prompt emission calculations (performed with the DSE model code) by using reliable pre-neutron fragment distributions Y(A,TKE) (5 sets of experimental data and a calculated one) and two fragmentation ranges (deterministically constructed by using reliable sets of the charge polarization ΔZ(A) and rms(A) of the isobaric charge distribution). As TXE partitions, beside that based on modeling at scission, another one based this time on the so-called “experimental temperature ratio R_T” provided by a new method (without resorting to prompt emission model calculations for the fit of ν(A) data as other codes do) was employed. This study not only confirmed and strengthened the previously observed features of how the structures of Y(A_p) and Y(N_p) are influenced by model ingredients and Y(A,TKE) but also has revealed that the most significant influence on prompt emission and all post-neutron fragment distributions is that of the TXE partition. The good description of existing experimental data of Y(Z,A_p), Y(A_p), KE_p(Z), KE_p(A_p) for ²³³U(n_th,f) by the DSE results obtained with the TXE partition based on modeling at scission and several Y(A,TKE) can be considered as an indirect validation of these Y(A,TKE) distributions of pre-neutron fragments. The sawtooth shape of the nice correlation between the excitation energy E* of fully accelerated pre-neutron fragments and KE_p of post neutron fragments (looking as a reflection in mirror of the sawtooth shape of ν(A)) is maintained regardless of the employed fragmentation range, TXE partition and Y(A,TKE). The almost perfect overlap of E*(KE_p) in the case of ^{235, 233}U(n_th,f) (which might seem intuitive because the even-even compound nuclei ^{236, 234}U undergoing fission are close neighbors with similar nuclear properties) is explained in detail by investigating the beahviours of all physical quantities and distributions which are involved in this correlation.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01662-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073760","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":"Deciphering the origins of the elements through galactic archeology","authors":"Khalil Farouqi,&nbsp;Anna Frebel,&nbsp;Friedrich-Karl Thielemann","doi":"10.1140/epja/s10050-025-01668-5","DOIUrl":"10.1140/epja/s10050-025-01668-5","url":null,"abstract":"<div><p>Low-metallicity stars preserve the signatures of the first stellar nucleosynthesis events in the Galaxy, as their surface abundances reflect the composition of the interstellar medium from the time when they were born. Aside from primordial Big Bang nucleosynthesis, massive stars, due to their short lifetimes, dominate the wind and explosive ejecta into the interstellar medium of the early Galaxy. Most of them will end as core-collapse supernova (CCSN) explosions, and typical ejected abundance distributions, e.g. in terms of the <span>(alpha )</span>-element-to-Fe ratios, reflect these contributions. Essentially all CCSNe contribute ⁵⁶Fe (decaying from radioactive ⁵⁶Ni). Therefore, low-metallicity stars can be used to test whether the abundances of any other elements are correlated with those of Fe, i.e. whether these elements have been co-produced in the progenitor sources or if they require either a different or additional astrophysical origin(s). The present analysis focuses on stars with [Fe/H]&lt;-2, as they probe the earliest formation phase of the Galaxy when only one or very few nucleosynthesis events had contributed their ejecta to the gas from which the lowest metallicity stars form. This was also the era before low and intermediate mass stars (or type Ia supernovae) could contribute any additional heavy elements. Following earlier work on the origin of heavy r-process elements [1], we extend the present study to examine Pearson and Spearman correlations of Fe with Li, Be, C, N, O, Na, Mg, Si, S, K, Ca, Ti, Cr, Ni, Zn, Ge, Se, Sr, Y, Zr, Mo, Ba, La, Ce, Sm, Eu, Gd, Dy, Yb, Lu, Hf, Os, Ir, Pb, and Th, using high-resolution stellar abundance data from the SAGA [2] and JINA [3] databases. The main goal is to identify which of the observed elements (i) may have been co-produced with Fe in (possibly a variety of) CCSNe, and which elements require (ii) either a completely different, or (iii) at least an additional astrophysical origin.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01668-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037344","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":"Distribution functions of (varLambda ) and (varSigma ^0) baryons","authors":"Yang Yu,&nbsp;Peng Cheng,&nbsp;Hui-Yu Xing,&nbsp;Daniele Binosi,&nbsp;Craig D. Roberts","doi":"10.1140/epja/s10050-025-01672-9","DOIUrl":"10.1140/epja/s10050-025-01672-9","url":null,"abstract":"<div><p>Treating baryons as quark + interacting-diquark bound states, a symmetry-preserving formulation of a vector<span>(,times ,)</span>vector contact interaction (SCI) is used to deliver an extensive, coherent set of predictions for <span>(varLambda , varSigma ^0)</span> baryon unpolarised and polarised distribution functions (DFs) – valence, glue, and four-flavour separated sea – and compare them with those of a like-structured nucleon. <span>(varLambda , varSigma ^0)</span> baryons are strangeness negative-one isospin partners within the SU(3)-flavour baryon octet. This makes such structural comparisons significant. The study reveals impacts of diquark correlations and SU(3)-flavour symmetry breaking on <span>(varLambda )</span>, <span>(varSigma ^0)</span> structure functions, some of which are significant. For instance, were it not for the presence of axialvector diquarks in the <span>(varSigma ^0)</span> at the hadron scale, the <i>s</i> quark could carry none of the <span>(varSigma ^0)</span> spin. The discussion canvasses issues that include helicity retention in hard scattering processes; the sign and size of polarised gluon DFs; and the origin and decomposition of baryon spins. Interpreted judiciously, the SCI analysis delivers an insightful explanation of baryon structure as expressed in DFs.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037358","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":"Theoretical investigation of near yrast bands in odd-mass (^{123-131})La isotopes","authors":"Ritvik Gupta,&nbsp;Aneeqa Basheer,&nbsp;Suram Singh,&nbsp;Manvi Rajput,&nbsp;G. H. Bhat,&nbsp;J. A. Sheikh,&nbsp;Arun Bharti","doi":"10.1140/epja/s10050-025-01684-5","DOIUrl":"10.1140/epja/s10050-025-01684-5","url":null,"abstract":"<div><p>Theoretical investigation of negative parity bands in odd-mass <span>(^{123-131})</span>La isotopes has been carried out by using Triaxial Projected Shell Model approach (TPSM). Potential Energy Surface (PES) calculations suggest <span>(gamma )</span>-soft nature of these isotopes. This finding is further supported by an analysis of their quadrupole shape invariants, which indicates that the nuclei have a soft-triaxial shape. Suitable deformation parameters, which are in agreement with the previous studies, are used to generate the band energies of the yrast band, <span>(gamma )</span>-band, and their signature partners. The bandhead energies of all the bands are in good agreement with the experimental values. Further, structural properties like band diagrams, backbending in moment of inertia, dynamic moment of inertia, signature splitting and reduced transition probabilities (B(E2) and B(M1)) have also been calculated.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 9","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037503","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}