The European Physical Journal A最新文献

{"title":"The Felsenkeller shallow-underground laboratory for nuclear astrophysics","authors":"Daniel Bemmerer,&nbsp;Axel Boeltzig,&nbsp;Marcel Grieger,&nbsp;Katharina Gudat,&nbsp;Thomas Hensel,&nbsp;Eliana Masha,&nbsp;Max Osswald,&nbsp;Bruno Poser,&nbsp;Simon Rümmler,&nbsp;Konrad Schmidt,&nbsp;José Luis Taín,&nbsp;Ariel Tarifeño-Saldivia,&nbsp;Steffen Turkat,&nbsp;Anup Yadav,&nbsp;Kai Zuber","doi":"10.1140/epja/s10050-025-01490-z","DOIUrl":"10.1140/epja/s10050-025-01490-z","url":null,"abstract":"<div><p>In the Felsenkeller shallow-underground site, protected from cosmic muons by a 45 m thick rock overburden, a research laboratory including a 5 MV Pelletron ion accelerator and a number of radioactivity-measurement setups is located. The laboratory and its installations are described in detail. The background radiation has been studied, finding suppression factors of 40 for cosmic-ray muons, 200 for ambient neutrons, and 100 for the background in germanium <span>(gamma )</span>-ray detectors. Using an additional active muon veto, typically the background is just twice as high as in very deep underground laboratories. The properties of the accelerator including its external and internal ion sources and beam line are given. For the radioactivity counting setup, detection limits in the 10<span>(^{-4})</span> Bq range have been obtained. Practical aspects for the usage of the laboratory by outside scientific users are discussed.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-025-01490-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109894","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":"Some results of 209Bi photoactivation experiment","authors":"M. Krmar,&nbsp;R. Smolović,&nbsp;N. Jovančević,&nbsp;D. Maletić,&nbsp;Y. Teterev,&nbsp;S. Mitrofanov,&nbsp;K. D. Timoshenko,&nbsp;S. I. Alexeev,&nbsp;H. Marukyan,&nbsp;A. Hakobyan","doi":"10.1140/epja/s10050-024-01479-0","DOIUrl":"10.1140/epja/s10050-024-01479-0","url":null,"abstract":"<div><p>Photoactivation of a natural bismuth target was performed in bremsstrahlung beams with maximum energies of 40 MeV, 50 MeV and 60 MeV. Several products of (γ,xn) reactions were identified in the gamma spectra and saturation activities and flux averaged sections were calculated for them. The obtained values were compared with the results based on TALYS estimates of the cross sections of the observed reactions. TALYS estimates were calculated for all combinations of photon strength function and level density (a total of 54 of them) with the intention of evaluating which of them shows the best agreement with the experimental results. The minimum and maximum estimates of the saturation activity obtained from the 54 photon SF and LD model combinations differ in most cases by an order of magnitude. The experimental values fall within this range. At 60 MeV, the experimental values of the saturation activity are lower than most TALYS estimates. A similar result is observed at 50 MeV, but to a somewhat lesser extent, while at 40 MeV, approximately the same number of saturation activities obtained from the TALYS cross-sections give both higher and lower estimates compared to the experiment. The flux averaged cross sections calculated using the TENDL estimates are two to three times larger than the experimental ones. By comparing experimental and theoretical values of flux-averaged cross sections for the formation of ²⁰⁶Bi, it was observed that good agreement was shown by those combinations of SF and LD models that are phenomenological in their formulation. No such trend was observed for other bismuth isotopes. There is a significant need to measure the cross sections of nuclear reactions with a higher multiplicity of emitted particles to provide experimental material for further development of models for calculating reaction cross sections.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109896","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":"Partial-wave analysis to determine the spin of (Xi (1690)^{-}) and (Xi (1820)^{-}) produced in (overline{p}p) annihilation","authors":"Deepak Pachattu","doi":"10.1140/epja/s10050-025-01492-x","DOIUrl":"10.1140/epja/s10050-025-01492-x","url":null,"abstract":"<div><p>Recently (The PANDA collaboration, arXiv:2201.03852v2) the PANDA collaboration studied the feasibility of determining the spin and parity of the <span>(Xi (1690)^{-})</span> and <span>(Xi (1820)^{-})</span> resonances in the <span>(Lambda K^-)</span> system produced in <span>(bar{p}p)</span> collisions via the reaction channel <span>(overline{p} p rightarrow bar{Xi }^{+} Lambda K^{-})</span>. The present paper aims to study these reactions using a model-independent irreducible tensor formalism developed earlier. This study leads us to identify the partial-wave amplitude and the observable, which would be zero if <span>(Xi (1690)^{-})</span> or <span>(Xi (1820)^{-})</span> had spin-1/2, provided these resonances are produced at threshold (s-wave production).</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109358","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":"Ab initio Bogoliubov many-body perturbation theory: closed-form constraint on the average particle number","authors":"P. Demol,&nbsp;T. Duguet,&nbsp;A. Tichai","doi":"10.1140/epja/s10050-024-01480-7","DOIUrl":"10.1140/epja/s10050-024-01480-7","url":null,"abstract":"<div><p>Bogoliubov many-body perturbation theory (BMBPT) relying on the breaking of <i>U</i>(1) global gauge symmetry has been recently formulated and applied to extend the applicability of standard perturbation theory to ab initio calculations of atomic nuclei away from shell closures. So far, practical applications have been limited to second-order calculations due to the lack of a generic algorithm to constrain the average particle number of the symmetry-broken state. This limitation is presently lifted and a general BMBPT formalism is presented that allows to constrain the particle-number expectation value at arbitrary order <i>P</i>. The constraint can be incorporated in closed form by solving a polynomial equation of degree <span>(P-1)</span>. The numerical procedure is illustrated through BMBPT(3) calculations of calcium isotopes using a nuclear Hamiltonian derived within chiral effective field theory.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109706","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":"Charged hadron spectra and anisotropic flow from the AMPT model with shear viscous transport dynamics simulations at RHIC","authors":"Yao Zhang","doi":"10.1140/epja/s10050-025-01498-5","DOIUrl":"10.1140/epja/s10050-025-01498-5","url":null,"abstract":"<div><p>We utilized the AMPT model to simulate the shear viscous transport dynamics of parton matter in Au + Au collisions at a constant specific shear viscosity and varying phase transition temperatures at <span>(sqrt{s_{NN}}=200,textrm{GeV})</span>. The resulting charged hadron spectra and anisotropic flow profiles correspond closely with experimental data. The transverse momentum spectra and longitudinal decorrelations are essentially unaffected by the phase transition temperature. An increase in the phase transition temperature leads to a rise in particle yields at midrapidity, accompanied by a decrease in both elliptic and triangular flows over a range of transverse momenta and pseudorapidities.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109779","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":"Pseudoscalar and vector tetraquarks (bb{overline{c}}{overline{c}})","authors":"S. S. Agaev,&nbsp;K. Azizi,&nbsp;H. Sundu","doi":"10.1140/epja/s10050-024-01476-3","DOIUrl":"10.1140/epja/s10050-024-01476-3","url":null,"abstract":"<div><p>The pseudoscalar and vector four-quark states <span>(bb{overline{c}}{overline{c}})</span> are studied in the context of the QCD sum rule method. We model <span>(T_{text { PS}} )</span> and <span>(T_{text {V}})</span> as structures built of diquarks <span>( b^{T}Cgamma _{5}b)</span>, <span>({overline{c}}C{overline{c}}^{T})</span> and <span>(b^{T}Cgamma _{5}b)</span>, <span>({overline{c}}Cgamma _{mu }gamma _{5}{overline{c}}^{T})</span>, respectively, with <i>C</i> being the charge conjugation matrix. The spectroscopic parameters of the tetraquarks <span>(T_{text {PS}})</span> and <span>(T_{text {V}})</span>, i.e., their masses and current couplings are calculated using QCD two-point sum rule method. We evaluate the full widths of <span>(T_{text {PS}})</span> and <span>(T_{text {V}})</span> by taking into account their kinematically allowed decay channels. In the case of the pseudoscalar particle they are processes <span>(T_{text {PS}} rightarrow B_{c}^{-}B_{c}^{*-})</span>, <span>(B_{c}^{-}B_{c}^{-}(1^{3}P_{0}))</span> and <span>(B_{c}^{*-}B_{c}^{-}(1^{1}P_{1}))</span>. The vector state <span>(T_{text {V}})</span> can dissociate to meson pairs <span>(2 B_{c}^{-})</span>, <span>(2 B_{c}^{*-})</span> and <span>( B_{c}^{-}B_{c}^{-}(1^{1}P_{1}))</span>. Partial widths of these decays are determined by the strong couplings at relevant tetraquark-meson-meson vertices, which evaluated in the context of the three-point sum rule approach. Predictions obtained for the mass and full width of the pseudoscalar <span>(m =(13.092pm 0.095)~text {GeV})</span>, <span>(Gamma _{text {PS} }=(63.7pm 13.0)~text {MeV})</span> and vector <span>({widetilde{m}} =(13.15pm 0.10)~ text {GeV})</span>, <span>(Gamma _{text {V}}=(53.5pm 10.3)~text {MeV})</span> tetraquarks can be useful for analyses of different four-quark resonances.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109656","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 new way to unravel the (^{12})C((alpha ),(gamma ))(^{16})O cross section components using neural networks","authors":"J. G. Duarte,&nbsp;A. Di Leva,&nbsp;R. Buompane,&nbsp;A. Formicola,&nbsp;J. T. Harke,&nbsp;D. Rapagnani,&nbsp;C. Santonastaso,&nbsp;L. Gialanella","doi":"10.1140/epja/s10050-024-01478-1","DOIUrl":"10.1140/epja/s10050-024-01478-1","url":null,"abstract":"<div><p>The <span>(^{12})</span>C(<span>(alpha )</span>,<span>(gamma )</span>)<span>(^{16})</span>O reaction rate is crucial in determining the carbon-to-oxygen abundance ratio in stellar nucleosynthesis. Measuring this reaction’s cross section at stellar energies is challenging due to its extremely small value, approximately 10<span>(^{-17})</span> barn at E<span>(_{mathrm {c.m.}})</span> = 300 keV. To address this, R-matrix calculations are employed to extrapolate data to lower energies, requiring a comprehensive understanding of each contribution to the cross section. The dominant contributions to the cross section at stellar energies arise from electric dipole (E1) and electric quadrupole (E2) transitions to the ground state of <span>(^{16})</span>O, along with a significant cascade contribution. Traditionally, these contributions have been separated using the <span>(gamma )</span>-ray angular distribution. In this work, we propose a novel technique using the energy distribution of the <span>(^{16})</span>O recoils at the focal plane. This method involves a neural network trained on detailed Monte Carlo simulations of the energy distribution of recoils transported through the recoil mass separator ERNA. This approach enables the simultaneous determination of all three contributions with errors around 10% in the energy range E<span>(_{mathrm {c.m.}})</span> = 1.0–2.2 MeV. By employing this new technique, we aim to significantly improve the accuracy of determining the cross section of the <span>(^{12})</span>C(<span>(alpha )</span>,<span>(gamma )</span>)<span>(^{16})</span>O reaction at astrophysical energies.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109391","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":"Determination of photonuclear cross section of 58Co((gamma ,)xp) reaction in the energy region 27–32 MeV via the surrogate ratio method","authors":"Shaima Akbar,&nbsp;M. M. Musthafa,&nbsp;C. V. Midhun,&nbsp;S. V. Suryanarayana,&nbsp;Jyoti Pandey,&nbsp;Bhawna Pandey,&nbsp;A. Pal,&nbsp;P. C. Rout,&nbsp;S. Santra,&nbsp;Antony Joseph,&nbsp;K. C. Jagadeesan,&nbsp;S. Ganesan","doi":"10.1140/epja/s10050-025-01485-w","DOIUrl":"10.1140/epja/s10050-025-01485-w","url":null,"abstract":"<div><p>The photonuclear reaction cross section of ⁵⁸Co(<span>(gamma ,)</span>xp) reaction has been measured for the first time by employing the surrogate reaction technique. The cross section of the photonuclear reaction is obtained in the energy region 27–32 MeV. The compound nucleus ⁵⁸<span>(hbox {Co}^{*})</span> was populated using the transfer reaction ⁵⁶Fe(⁶Li,<span>(alpha )</span>) at <span>(hbox {E}_{lab}=)</span> 35.9 MeV. To calculate the surrogate ratio, ⁶¹Ni(<span>(gamma )</span>,xp) was selected as the reference reaction and the corresponding compound nucleus ⁶¹<span>(hbox {Ni}^{*})</span> was populated using the transfer reaction ⁵⁹Co(⁶Li,<span>(alpha )</span>) at <span>(hbox {E}_{lab}=)</span> 40.5 MeV. Reference data taken from the recommended IAEA photonuclear database, which adopted the KAERI data in this case, have been used to determine the desired cross section. Compound nuclear cross section calculations have been done using the statistical nuclear reaction code TALYS 1.96.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109394","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":"Gluonic hidden-charm tetraquark states","authors":"Bing-Dong Wan,&nbsp;Shuo Yang","doi":"10.1140/epja/s10050-024-01475-4","DOIUrl":"10.1140/epja/s10050-024-01475-4","url":null,"abstract":"<div><p>In this paper, a new type of hybrid state, which consists of two valence quarks and two valence antiquarks together with a valence gluon, the gluonic tetraquark states, are investigated. Twenty-four currents of the the gluonic hidden-charm tetraquark states in <span>([bar{3}_c]_{c q}otimes [8_c]_{G}otimes [3_c]_{bar{c} bar{q^prime }})</span> configuration are constructed, and their mass spectrum are evaluated in the framework of QCD sum rules with quantum numbers of <span>(J^P=0^{+})</span>, <span>(0^{-})</span>, <span>(1^{-})</span>, and <span>(1^{+})</span>. The nonperturbative contributions up to dimension 8 are taken into account. The results indicate that there may be exist 14 gluonic hidden-charm tetraquark states, and their corresponding hidden-bottom partners are also evaluated. The possible production and decay modes of the gluonic tetraquark states are analyzed, which are hopefully measurable in BESIII, BELLEII, PANDA, Super-B, and LHCb experiments.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109381","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":"Investigation on the electromagnetic properties of the ( D^{(*)} Sigma _c^{(*)}) molecules","authors":"Ulaş Özdem","doi":"10.1140/epja/s10050-024-01477-2","DOIUrl":"10.1140/epja/s10050-024-01477-2","url":null,"abstract":"<div><p>We systematically explore their electromagnetic characteristics to improve our understanding of the quark-gluon dynamics underlying the complex and controversial nature of multiquark systems. In this study, the magnetic dipole moments of <span>( D Sigma _c)</span>, <span>( D Sigma _c^{*})</span> and <span>( D^{*} Sigma _c)</span> doubly-charmed pentaquarks are extracted, which are directly related to the inner organization of the relevant states. The magnetic dipole moments of these pentaquarks are evaluated employing the QCD light-cone sum rules technique with isospin spin-parity <span>(mathrm{I(J^P)} = frac{1}{2}(frac{1}{2}^-))</span>, <span>(mathrm{I(J^P)} = frac{1}{2}(frac{3}{2}^-))</span> and <span>(mathrm{I(J^P)} = frac{1}{2}(frac{3}{2}^-))</span>, for <span>( D Sigma _c)</span>, <span>( D Sigma _c^{*})</span> and <span>( D^{*} Sigma _c)</span> doubly-charmed pentaquarks, respectively. Our predictions for the magnetic dipole moment <span>(mu _{DSigma _c} = 2.98^{+0.76}_{-0.54}~mu _N)</span> for the <span>( D Sigma _c)</span> pentaquark, <span>(mu _{DSigma _c^*} = 1.65^{+0.45}_{-0.34}~mu _N)</span> for the <span>(DSigma _c^*)</span> pentaquark, and <span>(mu _{D^*Sigma _c} = -3.63^{+0.79}_{-0.60}~mu _N)</span> for the <span>(D^*Sigma _c)</span> pentaquark. Furthermore, we have also extracted the electric quadrupole and the magnetic octupole moments of the <span>( D Sigma _c^{*})</span> and <span>( D^{*} Sigma _c)</span> doubly-charmed pentaquarks. These values show a non-spherical charge distribution. As a by-product, the magnetic dipole moments of the isospin-<span>(frac{3}{2})</span> partners associated with these doubly-charmed pentaquarks have also been determined. The magnetic dipole moments are calculated as follows: <span>(mu _{DSigma _c} = 3.78^{+0.94}_{-0.70}~mu _N)</span>, <span>( mu _{DSigma _c^*} = 2.08^{+0.57}_{-0.43}~mu _N)</span>, <span>(mu _{D^*Sigma _c} = -4.59^{+0.99}_{-0.76}~mu _N)</span> for the isospin-<span>(frac{3}{2})</span> partners <span>( D Sigma _c)</span>, <span>( D Sigma _c^{*})</span> and <span>( D^{*} Sigma _c)</span> doubly-charmed pentaquarks, respectively. We hope that our predictions of the magnetic dipole moments of the doubly-charmed pentaquarks, in conjunction with the results of other theoretical investigations of the spectroscopic parameters and decay widths of these intriguing pentaquarks, will prove valuable in the search for these states in future experiments and in elucidating the internal structure of these pentaquarks.</p></div>","PeriodicalId":786,"journal":{"name":"The European Physical Journal A","volume":"61 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epja/s10050-024-01477-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109148","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}