Nuclear Physics A最新文献

{"title":"Description of the processes e+e− → π+π− and τ− → π−π0ντ in the NJL model with value of the vector coupling constant gρ = 6","authors":"M.K. Volkov ,&nbsp;A.A. Pivovarov ,&nbsp;K. Nurlan","doi":"10.1016/j.nuclphysa.2024.122992","DOIUrl":"10.1016/j.nuclphysa.2024.122992","url":null,"abstract":"<div><div>It is shown that the processes <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> and <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mi>τ</mi></mrow></msub></math></span> can be described in a unified approach in satisfactory agreement with experiment using the vector coupling constant <span><math><msub><mrow><mi>g</mi></mrow><mrow><mi>ρ</mi></mrow></msub><mo>=</mo><mn>6</mn></math></span>. In this case, in addition to quark loops, it is also necessary to take into account meson loops corresponding to the next order in <span><math><mn>1</mn><mo>/</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span>. These loops must be taken into account when describing the <span><math><mi>γ</mi><mo>(</mo><mi>W</mi><mo>)</mo><mo>→</mo><mi>ρ</mi></math></span> transition, as well as in interaction of mesons in the final state.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1054 ","pages":"Article 122992"},"PeriodicalIF":1.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746328","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}

{"title":"Measurement of charge-changing cross section of neutron-rich nitrogen isotopes for determining their proton radii","authors":"A. Roy ,&nbsp;R. Kanungo ,&nbsp;D. Prajapati ,&nbsp;Y.K. Tanaka ,&nbsp;S. Bagchi ,&nbsp;H. Geissel ,&nbsp;P. Doornenbal ,&nbsp;W. Horiuchi ,&nbsp;D.S. Ahn ,&nbsp;H. Baba ,&nbsp;K. Behr ,&nbsp;F. Browne ,&nbsp;S. Chen ,&nbsp;M.L. Cortés ,&nbsp;A. Estradé ,&nbsp;N. Fukuda ,&nbsp;M. Holl ,&nbsp;K. Itahashi ,&nbsp;N. Iwasa ,&nbsp;W.G. Jiang ,&nbsp;K. Yoshida","doi":"10.1016/j.nuclphysa.2024.122983","DOIUrl":"10.1016/j.nuclphysa.2024.122983","url":null,"abstract":"<div><div>A systematic study of point proton radii along an isotopic chain provides insights into the impact of the extended neutron wavefunction on the protons. This work aims to measure the charge-changing cross section (<span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math></span>) for neutron-rich <span><math><mmultiscripts><mrow><mtext>N</mtext></mrow><mprescripts></mprescripts><none></none><mrow><mn>23</mn></mrow></mmultiscripts></math></span>, marking the first determination of its point proton root mean square radius, as well as the <span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math></span> for <span><math><mmultiscripts><mrow><mtext>N</mtext></mrow><mprescripts></mprescripts><none></none><mrow><mn>21</mn><mo>,</mo><mn>22</mn></mrow></mmultiscripts></math></span> at beam energies around 250<em>A</em> MeV.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1054 ","pages":"Article 122983"},"PeriodicalIF":1.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721571","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}

{"title":"Mass resolved angular distribution of fission products in 12C+232Th reaction at sub-barrier energy","authors":"S. Kumar ,&nbsp;S. Patra ,&nbsp;A. Mhatre ,&nbsp;A. Kumar ,&nbsp;K. Ramachandran ,&nbsp;R. Tripathi","doi":"10.1016/j.nuclphysa.2024.122985","DOIUrl":"10.1016/j.nuclphysa.2024.122985","url":null,"abstract":"<div><div>This article reports the study of mass resolved angular distribution of the fission products and the angular anisotropy in ²³²Th(¹²C,f) reaction at sub-barrier energy to investigate the possible role of shell effects and non-compound nucleus fission. In literature, average anisotropy values reported earlier for this system at sub-barrier energy widely vary. The present study was carried out using the recoil catcher technique followed by off-line γ-ray spectrometry at 62.5 MeV beam energy. Angular anisotropies of fission products showed slight enhancement in the symmetric mass region. Significantly higher value of the experimental average anisotropy (1.46 ± 0.06) compared to that obtained by Statistical Saddle Point Model (SSPM) calculation indicated the possible role of shell effect and non-compound nucleus fission at the present beam energy. Consideration of shell effects resulted in an enhancement of the calculated anisotropy, though it was still slightly lower compared to the experimental value. The contribution from the non-compound nucleus fission was confirmed based of the deviation of the SSPM calculation in the symmetric mass region, where shell effects are not expected to be significant. In order to reproduce the error weighted average anisotropy (1.73 ± 0.18) for the symmetric mass region, the required value for the variance of <em>K</em>-distribution was much lower compared to the value obtained from the SSPM calculations. Presence of insignificant mass dependence of anisotropy suggests quasifission to be the dominant non-compound nucleus fission mechanism for the present system at the sub-barrier energy. This is consistent with the earlier studies [Mein <em>et al.</em>, Phys. Rev. C55 (1997) R995; Williams <em>et al.</em> Phys. Rev. C 88 (2013) 034611] attributing anomaly in the overall fission fragment angular distribution to the contribution from quasifission.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1054 ","pages":"Article 122985"},"PeriodicalIF":1.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746327","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}

{"title":"Quarkyonic equation of state with momentum-dependent interaction and neutron star structure","authors":"K. Folias,&nbsp;Ch.C. Moustakidis","doi":"10.1016/j.nuclphysa.2024.122982","DOIUrl":"10.1016/j.nuclphysa.2024.122982","url":null,"abstract":"<div><div>The structure and basic properties of dense nuclear matter still remain one of the open problems of Physics. In particular, the composition of the matter that composes neutron stars is under theoretical and experimental investigation. Among the theories that have been proposed, apart from the classical one where the composition is dominated by hadrons, the existence or coexistence of free quark matter is a dominant guess. An approach towards this solution is the phenomenological view according to which the existence of quarkyonic matter plays a dominant role in the construction of the equation of state (EOS). According to it the structure of the EOS is based on the existence of the quarkyonic particle which is a hybrid state of a particle that combines properties of hadronic and quark matter with a corresponding representation in momentum space. In this paper we propose a phenomenological model for quarkyonic matter, borrowed from corresponding applications in hadronic models, where the interaction in the quarkyonic matter depends not only on the position but also on the momentum of the quarkyonic particles. This consideration, as we demonstrate, can have a remarkable consequence on the shape of the EOS and thus on the properties of neutron stars, offering a sufficiently flexible model. Comparison with recent observational data can place constraints on the parameterization of the particular model and help improve its reliability.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1054 ","pages":"Article 122982"},"PeriodicalIF":1.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721570","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}

{"title":"What to expect from microscopic nuclear modelling for keff calculations?","authors":"D. Rochman ,&nbsp;A. Koning ,&nbsp;S. Goriely ,&nbsp;S. Hilaire","doi":"10.1016/j.nuclphysa.2024.122979","DOIUrl":"10.1016/j.nuclphysa.2024.122979","url":null,"abstract":"<div><div>Comparisons between predicted and benchmark k_eff values from criticality-safety systems are often used as metrics to estimate the quality of evaluated nuclear data libraries. Relevant nuclear data for these critical systems generally come from a mixture of expert knowledge and phenomenological predictions. In the present work, we use solely microscopic nuclear modelling from TALYS to estimate actinides cross sections and angular distributions, and we compare the calculated MCNP k_eff values for fast systems between the JEFF-3.3 evaluated library, phenomenological and microscopic modelling. The conclusion is that even if the evaluated library leads to the most adequate results, the microscopic nuclear modelling can reach very similar results for these integral quantities. It demonstrates the remarkable advances in the recent decades of microscopic nuclear reaction ingredients for applied integral observables.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1054 ","pages":"Article 122979"},"PeriodicalIF":1.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721666","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}

{"title":"QCD phase diagram and the finite volume fireball: A model study","authors":"Adiba Shaikh ,&nbsp;Ranjita K. Mohapatra ,&nbsp;Saumen Datta","doi":"10.1016/j.nuclphysa.2024.122981","DOIUrl":"10.1016/j.nuclphysa.2024.122981","url":null,"abstract":"<div><div>Experimental investigations of the phase diagram of strongly interacting matter involve collisions of heavy ions at ultrarelativistic velocities. The medium created in such a collision is often of dimensions a few fermi, in particular in the Beam Energy Scan experiments. An understanding of the effect of the finite volume and the boundary is important for connecting the experimental results to the phase diagram.</div><div>Using the Nambu Jona-Lasinio model, an effective theory for the chiral transition of quantum chromodynamics (QCD), we have studied the effect of the finite volume of the fireball on the transition line at finite temperature and density using the MIT boundary condition to mimic the condition that the system is deconfined inside. We studied the effect of the finite volume on the transition temperature and on number density and its susceptibilities. The volume effects should be considered when looking for signatures of the phase diagram in experiments.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1054 ","pages":"Article 122981"},"PeriodicalIF":1.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721667","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}

{"title":"Probing multi-particle bunching from intermittency analysis in relativistic heavy-ion collisions","authors":"Valeria Zelina Reyna Ortiz,&nbsp;Maciej Rybczyński,&nbsp;Zbigniew Włodarczyk","doi":"10.1016/j.nuclphysa.2024.122980","DOIUrl":"10.1016/j.nuclphysa.2024.122980","url":null,"abstract":"<div><div>It has been demonstrated that factorial moments analysis in dependence on the size of phase-space cells (when the latter is decreased but is still considerably large) exhibits sensitivity to particle bunching within a system situated in the two-dimensional cell. Based on recent findings concerning fluctuations in charge particle density observed in central Au + Au collisions at various energies ranging from <span><math><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>N</mi><mi>N</mi></mrow></msub></mrow></msqrt></math></span> = 7.7 to 200 GeV at RHIC/STAR, it is proposed that analyzing factorial moments in relativistic heavy-ion collisions could serve as a method to investigate density fluctuations linked to correlation phenomena. Our understanding of particle production mechanisms may be enriched by using factorial moments analysis to gain new information contained in them that was initiated four decades ago from observation of “spike” phenomena.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1053 ","pages":"Article 122980"},"PeriodicalIF":1.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652731","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}

{"title":"Investigation of the proton radius of the Borromean halo nucleus 19B","authors":"D. Prajapati ,&nbsp;R. Kanungo ,&nbsp;Y.K. Tanaka ,&nbsp;S. Bagchi ,&nbsp;H. Geissel ,&nbsp;P. Doornenbal ,&nbsp;W. Horiuchi ,&nbsp;D.S. Ahn ,&nbsp;H. Baba ,&nbsp;K. Behr ,&nbsp;F. Browne ,&nbsp;S. Chen ,&nbsp;M.L. Cortés ,&nbsp;A. Estradé ,&nbsp;N. Fukuda ,&nbsp;M. Holl ,&nbsp;K. Itahashi ,&nbsp;N. Iwasa ,&nbsp;W.G. Jiang ,&nbsp;S. Kaur ,&nbsp;K. Yoshida","doi":"10.1016/j.nuclphysa.2024.122977","DOIUrl":"10.1016/j.nuclphysa.2024.122977","url":null,"abstract":"<div><div>The charge-changing cross-section (<span><math><msub><mrow><mi>σ</mi></mrow><mrow><mi>c</mi><mi>c</mi></mrow></msub></math></span>) of the dripline nucleus, ¹⁹B, was measured using the transmission technique at RIBF, RIKEN, to understand its root mean square proton radius (<span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>). This new measurement will be the first determination of the <span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> for the Borromean nucleus, ¹⁹B. The new value of <span><math><msub><mrow><mi>R</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> will help determine the geometrical structure of ¹⁹B and the neutron-neutron correlation in the Borromean nucleus.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1053 ","pages":"Article 122977"},"PeriodicalIF":1.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652730","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}

{"title":"Re-visiting the role of short-range correlations on neutron-star properties","authors":"Sakshi Gautam ,&nbsp;Anagh Venneti ,&nbsp;Sarmistha Banik ,&nbsp;B.K. Agrawal","doi":"10.1016/j.nuclphysa.2024.122978","DOIUrl":"10.1016/j.nuclphysa.2024.122978","url":null,"abstract":"<div><div>The impact of short-range correlations (SRCs) on neutron star (NS) properties is re-examined across various classes of relativistic mean-field (RMF) models. The coupling strengths of the models are so adjusted that the low-density part of the equation of state (EoS), complemented with saturation properties such as binding energy of symmetric nuclear matter and nuclear symmetry energy responsible for the bulk properties of finite nuclei, remains practically unaffected with the inclusion of SRCs. The EoS for symmetric nuclear matter and the nuclear symmetry energy at supra-saturation densities which governs the EoS for NS matter become softer or stiffer in the presence of the SRCs, depending on the type of RMF model considered. These distinct effects of SRCs are observed to be more significant at higher densities, as expected, when behaviour of the EoS at low densities, which govern the finite nuclei physics, is not compromised. For most of the models with self-couplings of scalar and vector mesons, the EoS of symmetric nuclear matter stiffens, with a slight effect on nuclear symmetry energy with the inclusion of SRCs. Conversely, in the models incorporating cross-couplings between mesons, the addition of SRCs leads to softer symmetry energy, compensating the stiffening effect of the EoS of symmetric nuclear matter. With the inclusion of SRCs, the values of radius and tidal deformability of canonical mass star and maximum mass of NSs for realistic EoSs align well the present constraints on astrophysical observations.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1053 ","pages":"Article 122978"},"PeriodicalIF":1.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652732","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}

{"title":"Elucidating shell/subshell closure and the critical impact of isospin-asymmetry on barium isotopes using relativistic mean-field approach","authors":"N. Biswal ,&nbsp;Praveen K. Yadav ,&nbsp;R.N. Panda ,&nbsp;S. Mishra ,&nbsp;M. Bhuyan","doi":"10.1016/j.nuclphysa.2024.122975","DOIUrl":"10.1016/j.nuclphysa.2024.122975","url":null,"abstract":"<div><div>The aspect of structural evolution and the correlation of the properties of the ground state with the effective symmetry energy and its coefficients is examined for neutron-rich <em>even-even</em> isotopes of barium nuclei (<em>Z</em> = 56). The nuclear bulk properties such as binding energy, root-mean-square charge radius, quadrupole deformation, two neutron separation energy, and two neutron shell gaps are calculated using the axially deformed relativistic mean field formalism for nonlinear NL3^⁎ and density-dependent sets of DD-ME2 force parameters. The calculated results are further compared with the available experimental data and other theoretical models. The results of the bulk nuclear properties indicate <em>N</em> = 82 as a neutron shell closure near the neutron-rich side of the isotopic chain of Ba nuclei. Alternatively, a systematic analysis of isospin-dependent observables, such as the nuclear symmetry energy and its volume and surface components, is estimated along the isotopic chain, which is crucial for studying shell/subshell closure away from the <em>β</em>-stability line. This work incorporates two types of relativistic mean-field densities as inputs. Firstly, the spherical density using the NL3* and DD-ME2 parameter sets. Secondly, for comparison, the monopole component of the multipole expanded deformed density using the DD-ME2 parameter. From the isospin-dependent properties, we observe that both the spherical and monopole components of the deformed density follow a similar trend along the isotopic chain. The isospin-dependent quantities are in accordance with the nuclear bulk properties while verifying the traditional shell closure at <em>N</em> = 82 for the neutron-rich Ba nuclei. In addition, we noticed a significant peak near <em>N</em> = 58, indicating greater stability than its neighbouring nuclei. Consequently, this study provides a novel region of interest for isospin-based experimental and theoretical studies. Furthermore, the present investigation is quite relevant for understanding the role of isospin-asymmetry in the variation of nuclear properties, which is pivotal for elucidating the synthesis of exotic nuclei along the nuclear chart.</div></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":"1053 ","pages":"Article 122975"},"PeriodicalIF":1.7,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560699","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}