The European Physical Journal A最新文献

{"title":"Calculation of tetraneutron-induced reaction cross sections with optical and Hauser–Feshbach statistical models","authors":"Hiroyuki Fujioka,&nbsp;Toshihiko Kawano","doi":"10.1140/epja/s10050-026-01928-y","DOIUrl":"10.1140/epja/s10050-026-01928-y","url":null,"abstract":"<div><p>Interactions of tetraneutrons, which are assumed to be produced in the nuclear fission process, with nuclei are studied in the framework of optical and Hauser–Feshbach statistical models. It predicts a large probability of <span>(^{89})</span>Sr production for the tetraneutron-induced reaction on <span>(^{88})</span>Sr compared to other isotopes. The same technique is applied to the tetraneutron-induced reaction on <span>(^{27})</span>Al and the hexaneutron-induced reaction on natural zinc to revisit two historical multi-neutron experiments performed in the past.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751782","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":"Bremsstrahlung emission accompanying ternary fission of (^{252})Cf","authors":"Sergei P. Maydanyuk,&nbsp;Ju-Jun Xie,&nbsp;Sergiy O. Omelchenko","doi":"10.1140/epja/s10050-026-01915-3","DOIUrl":"10.1140/epja/s10050-026-01915-3","url":null,"abstract":"<div><p>In ternary fission, bremsstrahlung photons are emitted but those have never been studied yet theoretically and experimentally. In other reactions, bremsstrahlung has been studied for a long time. To clarify which new information about ternary fission can be obtained from study of bremsstrahlung emission accompanying the ternary fission of <span>(^{252})</span>Cf. A new quantum model of emission of bremsstrahlung photons accompanying ternary fission of heavy nuclei with <span>(alpha )</span> particle as light charged particle is developed. The model takes into account geometry and dynamics of ternary fission. We present the theoretical results on the bremsstrahlung emission in the ternary fission of the <span>(^{252})</span>Cf nucleus. High sensitivity of the bremsstrahlung spectra is established by the model concerning to the following aspects of the ternary fission, and the theoretical calculations are in agreement with the preliminary experimental data. It is found that: (a) Photons are emitted with highest intensity in case of perpendicular motion of the <span>(alpha )</span> particle concerning to fission axis; (b) Relative motion between heavy fragments reinforces significantly bremsstrahlung, leaving of <span>(alpha )</span> particle concerning to system of heavy fragments is less important; (c) Relative motion between two heavy fragments is faster, bremsstrahlung is more intensive. Theoretical study of bremsstrahlung in ternary fission of the <span>(^{252})</span>Cf nucleus shows high sensitivity of bremsstrahlung spectra on the geometry and dynamics of ternary fission process. It is expected that new information can be obtained by the model when new experimental measurements of bremsstrahlung in ternary fission of the <span>(^{252})</span>Cf nucleus are available.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751642","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":"Pandemonium free data for the JEFF-project","authors":"A. Algora,&nbsp;G. Alcalá,&nbsp;M. Estienne,&nbsp;M. Fallot,&nbsp;L. Giot,&nbsp;V. Guadilla,&nbsp;J. L. Tain,&nbsp;W. Gelletly,&nbsp;A. Porta,&nbsp;L. Le Meur,&nbsp;V. M. Bui,&nbsp;J. A. Briz,&nbsp;A.-A. Zakari-Issoufou","doi":"10.1140/epja/s10050-026-01931-3","DOIUrl":"10.1140/epja/s10050-026-01931-3","url":null,"abstract":"<div><p>Reactor decay heat is due to the decay of both fission products and neutron activated fuel and reactor materials. At relatively short cooling times it is dominated by the beta decay of fission products. The calculation of the decay heat contribution of a particular fission product depends on the proper assignment of the probability of population of each excited state in the daughter nucleus following beta decay. These decay probabilities and the energy distribution of the continuous beta spectra determine both the unrecoverable energy taken away by the neutrinos and the distribution of decay heat between gamma rays and beta particles. The latter is important for further radiation transport modeling, for instance to determine the volume over which the heat is deposited. This paper describes recent advances in measurement and modeling of selected fission products and the impact for JEFF evaluations.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-026-01931-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751641","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":"Systematics of fission time scales for (^{16,18})O+(^{194,198})Pt reactions","authors":"Rohit Sandal","doi":"10.1140/epja/s10050-026-01934-0","DOIUrl":"10.1140/epja/s10050-026-01934-0","url":null,"abstract":"<div><p>Statistical code (PACE) calculations were used to obtain the fission time scales using the experimental M<span>(^{pre})</span> values for <span>(^{16,18})</span>O+<span>(^{194,198})</span>Pt reactions (experiment was performed at the 15 UD Pelletron accelerator facility of the Inter University Accelerator Centre (IUAC), New Delhi) [1]. PACE provides baseline statistical (non-dissipative) prediction and the excess neutrons relative to PACE are interpreted as due to dynamical/transient effects. The extracted results are also combined with the results obtained from nearby systems available in the literature. Combining all these results systematics of fission time scales is presented here and an enhanced delay was observed for the shell-closed compound nucleus <span>(^{212})</span>Rn (N = 126) in the present data. The extracted effective fission delay times are further discussed in connection with previously measured evaporation residue and fission observables for the same reaction systems. The combined analysis provides a phenomenological framework for examining the dependence of effective fission delay times on fissility and N/Z. Also the present extracted fission delay times from excess pre-scission neutron multiplicities were interpreted in conjunction with the previously measured ER behaviour.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751409","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":"Constraining the quark-hadron phase transition with GW170817: implications for tidal deformability and post-merger signatures","authors":"S. Suhani,&nbsp;P. Priyanka","doi":"10.1140/epja/s10050-026-01923-3","DOIUrl":"10.1140/epja/s10050-026-01923-3","url":null,"abstract":"<div><p>The internal composition of neutron stars remains one of the most significant uncertainties in nuclear astrophysics, specifically regarding the possible existence of deconfined quark matter at extremely high nuclear densities. We aim to identify robust multi-messenger signatures of a hadron-quark phase transition by analyzing the relationship between static stellar properties, tidal deformability, and post-merger gravitational-wave dynamics. Utilization of a suite of hybrid Equations of State (EoS), including the JJ(VQCD) and OOS(DD2_FRG) models, and comparing them against purely nucleonic baselines. Using a Python-based pipeline, we model the mass–radius relationship as well as calculate dimensionless tidal deformability <span>((Lambda ))</span>. Further employment of universal relations to predict the peak post-merger frequency <span>((f_2))</span> and dynamical ejecta properties for a GW170817-like event. Hybrid models naturally reconcile the high-mass constraint of <span>(M ge 2.01 M_{odot })</span> with the “soft” tidal response <span>((tilde{Lambda } approx 300))</span> observed in GW170817. A significant finding is a characteristic shift in the post-merger regime: hybrid remnants exhibit <span>(f_2)</span> frequencies 300–500 Hz lower than hadronic models. This spectral softening is accompanied by an increase in dynamical ejecta mass, resulting in a kilonova transient up to 0.5 magnitudes brighter than those predicted by standard hadronic EoS. The strong correlation <span>((r approx -0.99))</span> between inspiral tidal parameters and post-merger frequency provides a “smoking gun” for identifying quark matter. These signatures offer a definitive diagnostic for detectors which are third generation like the Einstein Telescope to probe the QCD phase diagram.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751356","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":"A quark–hadron crossover study in (beta )-stable stellar matter","authors":"Domenico Logoteta","doi":"10.1140/epja/s10050-026-01920-6","DOIUrl":"10.1140/epja/s10050-026-01920-6","url":null,"abstract":"<div><p>We develop several equations of state (EOSs) for <span>(beta )</span>-stable dense hadronic matter at both zero and finite temperatures, considering the potential occurrence of a quark–hadron crossover transition. These scenarios can actually occur in various astrophysical contexts, such as in the postmerger compact object formed during binary neutron star (BNS) mergers, in core-collapse supernovae (CCSNe), or in the early stages of a newly formed neutron star (protoneutron star, PNS). In order to describe the hadronic phase we use the DDME2 model which is based on a relativistic-mean-field (RMF) theory, while for the quark phase we employ a popular version of the three-flavors Nambu–Jona–Lasinio (NJL) model. In the hadronic phase, in addition to nucleons and leptons, we examine the effects and implications of potential hyperon formation. The crossover transition is modeled on existing data from low density lattice Quantum Chromodynamics (QCD) calculations. For each model we study thermal and neutrino trapping effects on the matter composition and consequently on the EOS. We ultimately determine the PNS static structure integrating the Tolman–Oppenheimer–Volkoff (TOV) equations. Our findings indicate that the presence of hyperons significantly hinders the development of quark matter during a crossover transition. In fact, with hyperonic matter, it becomes quite challenging to differentiate between EOSs with and without a crossover. Conversely, if only nucleons are present in the hadronic phase, the EOS with a crossover transition is notably softer compared to the pure nucleonic one, making it theoretically possible to distinguish between the two EOSs. Additionally, we observe that in the presence of a crossover transition, neutrino trapping results in a stiffer EOS. This outcome is independent of the particle composition of the hadronic phase, whether hyperons are included or not.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751439","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":"The combined AGATA-DSSD set-up for the measurement of very small heavy-ion fusion cross sections","authors":"M. Del Fabbro,&nbsp;G. Montagnoli,&nbsp;A. M. Stefanini,&nbsp;M. Balogh,&nbsp;D. Brugnara,&nbsp;L. Corradi,&nbsp;O. Carletto,&nbsp;G. Colucci,&nbsp;E. Fioretto,&nbsp;F. Galtarossa,&nbsp;A. Goasduff,&nbsp;A. Gottardo,&nbsp;M. Loriggiola,&nbsp;D. Mengoni,&nbsp;T. Mijatovic,&nbsp;J. Pellumaj,&nbsp;S. Pigliapoco,&nbsp;S. Szilner,&nbsp;N. Toniolo,&nbsp;J. J. Valiente-Dobon,&nbsp;L. Zago","doi":"10.1140/epja/s10050-026-01941-1","DOIUrl":"10.1140/epja/s10050-026-01941-1","url":null,"abstract":"<div><p>We describe the data analysis methods and the characteristics of the combined set-up of the <span>(gamma )</span>-ray tracking spectrometer AGATA with two annular double sided silicon strip detectors (DSSD) (4” diameter) placed 5.65 cm upstream and downstream of the target, for the measurement of <span>(gamma )</span>-light particle coincidences in near- and sub-barrier heavy-ion fusion reactions. The DSSD cover the angular ranges <span>(theta _{lab}=139.6^o)</span>–<span>(162.7^o)</span> and <span>(=23.0^o)</span>–<span>(40.4^o)</span>, corresponding to a total solid angle <span>(simeq 26%)</span> of 4<span>(pi )</span>. The ohmic side of the DSSD is turned towards the target, so protons and <span>(alpha )</span> particles can be clearly identified. We show the relevant results obtained for the two systems <span>(^{28})</span>Si+<span>(^{12})</span>C and <span>(^{16})</span>O+<span>(^{12})</span>C down to very small cross sections in the tenths of nb range. Particle identification allows us to observe well-separated groups of protons and <span>(alpha )</span>’s populating low-energy levels of the various fusion-evaporation residues (ER). Relative fusion cross sections are obtained with a procedure described in detail, and the absolute cross section scale is fixed by complementary measurements using an electrostatic beam deflector set-up where the ER are directly detected down to a few <span>(upmu )</span>b. The AGATA+DSSD set-up is subject to significant improvements thanks to the scheduled increase of the number of <span>(gamma )</span> detectors, and to the possibility of installing silicon detector arrays covering a larger solid angle. This will open the possibility of measuring fusion cross sections near, and possibly below, 1nb.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751086","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":"Scission neutron emission for (^{252})Cf(sf), within the sudden approximation framework","authors":"F. Guezet,&nbsp;N. Carjan,&nbsp;M. Rizea","doi":"10.1140/epja/s10050-026-01927-z","DOIUrl":"10.1140/epja/s10050-026-01927-z","url":null,"abstract":"<div><p>At scission, a highly deformed nucleus splits into two fragments that can sometimes be accompanied by emission of a third, much lighter, partner. Experimentally, proton and alpha emission at times close to scission has been observed but scission neutrons have not been clearly identified so far. In this study, we focus, using a theoretical microscopic model, on the emission of neutrons at the moment of scission of <span>(^{252})</span>Cf. For this, approximate description of the scission process is proposed based on the solution of the bi-dimensional stationary Schrödinger equation, for the most probable mass division of <span>(^{252})</span>Cf(sf): <span>(A_L/A_H = 109/143)</span>. It considers a diabatic coupling between the neutron degree of freedom and the sudden changing neutron-nucleus potential during the scission process which is supposed to start when the radius of the neck separating the two fragments is <span>(approx )</span> 2 fm. The physical quantities analyzed in this work reveal that scission neutrons have specific characteristics. These neutrons are mainly emitted from the neck region. The sudden approximation used gives, for <span>(^{252})</span>Cf, an upper limit for the scission neutron multiplicity of 0.89 and 0.91 n/fission, depending on the type of neutron correlation considered (Independent or BCS). They should represent, at most, a quarter of the total prompt neutrons (3.69 n/fission) observed experimentally. Furthermore, the mean kinetic energy distribution of scission neutrons reveals the presence of a long high-energy tail extending far beyond the limit of evaporated neutrons. This study thus highlights a potential signature of the scission neutron component of prompt fission neutrons.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751145","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":"Rotational susceptibility of a hot and dense hadronic matter","authors":"Bhagyarathi Sahoo,&nbsp;Kshitish Kumar Pradhan,&nbsp;Dushmanta Sahu,&nbsp;Raghunath Sahoo","doi":"10.1140/epja/s10050-026-01938-w","DOIUrl":"10.1140/epja/s10050-026-01938-w","url":null,"abstract":"<div><p>We study the effect of global rotation on rotational susceptibilities (<span>(chi ^{(1)}_{omega })</span>, <span>(chi ^{(2)}_mathrm{omega })</span>, etc.), which quantify how much the system responds to small angular velocities, in a hadron resonance gas produced by ultra-relativistic heavy ion collisions. The higher-order rotational susceptibilities and their ratios are estimated in the presence and absence of baryon chemical potential (<span>(mu _textrm{B})</span>) in the system. The effect of particle spin (<i>s</i>) and system size (<i>R</i>) on the first- and second-order rotational susceptibility is explored. To consider a more realistic scenario, the effect of interactions between hadrons is taken into account by considering van der Waals-like interactions, which include both attractive and repulsive interactions. To validate our results, a comparison with the ideal HRG as a baseline and a 3-flavour NJL model is shown. A nuclear liquid–gas phase transition, which is the characteristic feature of the van der Waals hadron resonance gas model, absent in an ideal hadron gas model, is probed via global rotation.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750605","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":"The B(E2) anomaly: evidence for a low-lying mixed-symmetry collective excitation mode","authors":"Bo Cederwall,&nbsp;Chong Qi","doi":"10.1140/epja/s10050-026-01932-2","DOIUrl":"10.1140/epja/s10050-026-01932-2","url":null,"abstract":"<div><p>Exceptionally low values of the ratio of electric quadrupole transition rates, <span>(B_{4/2}equiv B(E2;4^+_1rightarrow 2^+_1)/B(E2;2^+_1rightarrow 0^+_{textrm{gs}})&lt;1)</span>, have been observed in neutron-deficient nuclei near <span>(Napprox 94)</span> (W, Os, Pt) and <span>(Napprox 62)</span> (Te, Xe) with few and comparable numbers of valence nucleons outside closed shells. Remarkably, the suppressed <span>(B_{4/2})</span> ratios coincide with low-lying energy level patterns characteristic of collective motion. Standard approaches, including large-scale shell model, collective models, and density functional theory, fail to reproduce this behavior, commonly referred to as the <span>(B_{4/2})</span> (or <i>B</i>(<i>E</i>2)) anomaly. Recent work has reproduced the effect in selected Pt and Os isotopes via mapping a triaxial rotor Hamiltonian onto the interacting boson model (IBM), attributing it to triaxial rotational motion. However, this interpretation is unexpected as collectivity typically emerges first through vibrational modes with increasing valence nucleon number along isotopic chains. Here, we address this discrepancy using an extended IBM Hamiltonian across nuclei exhibiting the anomaly, benchmarked against large-scale shell model calculations, and propose that the <i>B</i>(<i>E</i>2) anomaly arises from a low-lying mixed-symmetry collective mode that bridges single-particle and collective dynamics.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"62 8","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-026-01932-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148750872","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}