Nuclear Physics A最新文献

{"title":"Predictions for the sPHENIX physics program","authors":"Ron Belmont ,&nbsp;Jasmine Brewer ,&nbsp;Quinn Brodsky ,&nbsp;Paul Caucal ,&nbsp;Megan Connors ,&nbsp;Magdalena Djordjevic ,&nbsp;Raymond Ehlers ,&nbsp;Miguel A. Escobedo ,&nbsp;Elena G. Ferreiro ,&nbsp;Giuliano Giacalone ,&nbsp;Yoshitaka Hatta ,&nbsp;Jack Holguin ,&nbsp;Weiyao Ke ,&nbsp;Zhong-Bo Kang ,&nbsp;Amit Kumar ,&nbsp;Aleksas Mazeliauskas ,&nbsp;Yacine Mehtar-Tani ,&nbsp;Genki Nukazuka ,&nbsp;Daniel Pablos ,&nbsp;Dennis V. Perepelitsa ,&nbsp;Fanyi Zhao","doi":"10.1016/j.nuclphysa.2024.122821","DOIUrl":"10.1016/j.nuclphysa.2024.122821","url":null,"abstract":"<div><p><span>sPHENIX is a next-generation detector experiment at the Relativistic Heavy Ion Collider, designed for a broad set of jet and heavy-flavor probes of the Quark-Gluon Plasma created in </span>heavy ion collisions<span>. In anticipation of the commissioning and first data-taking of the detector in 2023, a RIKEN-BNL Research Center (RBRC) workshop was organized to collect theoretical input and identify compelling aspects of the physics program. This paper compiles theoretical predictions from the workshop participants for jet quenching, heavy flavor and quarkonia, cold QCD, and bulk physics measurements at sPHENIX.</span></p></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139465149","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":"State dependence of tunneling processes and thermonuclear fusion","authors":"Roberto Onofrio ,&nbsp;Carlo Presilla","doi":"10.1016/j.nuclphysa.2024.122830","DOIUrl":"10.1016/j.nuclphysa.2024.122830","url":null,"abstract":"<div><p>We discuss the sensitivity of tunneling processes to the initial preparation of the quantum state. We compare the case of Gaussian wave packets of different positional variances using a generalized Woods-Saxon potential for which analytical expressions of the tunneling coefficients are available. Using realistic parameters for barrier potentials we find that the usual plane wave approximation underestimates fusion reactivities by an order of magnitude in a range of temperatures of practical relevance for controlled energy production.</p></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139454662","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":"Nuclear mass predictions with the naive Bayesian model averaging method","authors":"X.Y. Zhang (张晓燕) ,&nbsp;W.F. Li (李伟峰) ,&nbsp;J.Y. Fang (方基宇) ,&nbsp;Z.M. Niu (牛中明)","doi":"10.1016/j.nuclphysa.2024.122820","DOIUrl":"10.1016/j.nuclphysa.2024.122820","url":null,"abstract":"<div><p>A naive Bayesian model averaging (NBMA) method is developed to predict nuclear masses. In the NBMA method, the weights of different models may be different for each nucleus, which are sensitive to the model accuracies to describe the nuclear masses of the isotopes and isotones with the same proton and neutron numbers of that nucleus. Therefore, there are remarkable local structures for the weights of different models on the nuclear chart, which well eliminates the local deviations between the model predictions and the experimental masses and thus achieves better accuracy of mass predictions than the traditional arithmetic mean method (AMM) and weighted average method (WAM). Based on the latest atomic mass evaluation of AME2020, the root-mean-square (rms) mass deviation of the NBMA method is 0.293 MeV, while the rms deviations of AMM and WAM are 0.634 and 0.361 MeV, respectively. This accuracy of the NBMA method is even 28% better than the best accuracy of the mass models used in the NBMA method. The extrapolation ability of the NBMA method is also verified with the experimental nuclear masses which are not used in the training of the NBMA method.</p></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139372878","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":"Axially symmetric quadrupole-octupole incorporating sextic potential","authors":"M. Chabab,&nbsp;A. El Batoul,&nbsp;L. El Ouaourti","doi":"10.1016/j.nuclphysa.2023.122818","DOIUrl":"10.1016/j.nuclphysa.2023.122818","url":null,"abstract":"<div><p><span>We present an extended application of the analytic quadrupole octupole axially symmetric model, originally employed to study the octupole deformation and vibrations in light actinides using an infinite well potential (IW). In this work, we extend the model's applicability to a broader range of nuclei exhibiting octupole deformation by incorporating a sextic potential instead of the Davidson potential. Similarly to conventional models, such as AQOA-IW (for infinite square potential) and AQOA-D (for the Davidson potential), our proposed model is referred to as AQOA-S. By employing the sextic potential, phenomenologically represented as </span><span><math><mi>v</mi><mo>(</mo><mover><mrow><mi>β</mi></mrow><mrow><mo>˜</mo></mrow></mover><mo>)</mo><mo>=</mo><msub><mrow><mi>a</mi></mrow><mrow><mn>1</mn></mrow></msub><msup><mrow><mover><mrow><mi>β</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mn>2</mn></mrow></msup><mo>+</mo><msub><mrow><mi>a</mi></mrow><mrow><mn>2</mn></mrow></msub><msup><mrow><mover><mrow><mi>β</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mn>4</mn></mrow></msup><mo>+</mo><msub><mrow><mi>a</mi></mrow><mrow><mn>3</mn></mrow></msub><msup><mrow><mover><mrow><mi>β</mi></mrow><mrow><mo>˜</mo></mrow></mover></mrow><mrow><mn>6</mn></mrow></msup></math></span><span>, we can derive analytical expressions for the energy spectra and transition rates (B(E1), B(E2), B(E3)). The energy spectra of the model are essentially governed by two critical parameters: </span><span><math><msub><mrow><mi>ϕ</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, indicating the balance between octupole and quadrupole strain, and <em>α</em>, a key factor in adjusting the shape and behavior of the spectra through the sextic potential. In terms of applications, the study encompasses five isotopes, namely ^222−226Ra and ^224,226Th. Significantly, our model demonstrates remarkable agreement with the corresponding experimental data, particularly for the recently determined B(EL) transition rates of ²²⁴Ra, surpassing the performance of the model that employs the Davidson potential. The stability of the octupole deformation in ²²⁴Ra adds particular significance to these findings.</p></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139372926","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":"Constraining the chirally motivated πΣ−K¯N models with the πΣ photoproduction mass spectra","authors":"A. Cieplý,&nbsp;P.C. Bruns","doi":"10.1016/j.nuclphysa.2024.122819","DOIUrl":"10.1016/j.nuclphysa.2024.122819","url":null,"abstract":"<div><p>The paper presents a first time attempt on a combined fit of the <span><math><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>p</mi></math></span> low-energy data and the <em>π</em><span>Σ photoproduction<span> mass spectra, performed without fixing the meson-baryon rescattering amplitudes to a specific </span></span><span><math><mi>π</mi><mi>Σ</mi><mo>−</mo><mover><mrow><mi>K</mi></mrow><mrow><mo>¯</mo></mrow></mover><mi>N</mi></math></span> coupled channels model obtained from fitting exclusively the <span><math><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>p</mi></math></span><span> data. The formalism adopted to describe the photoproduction process is based on chiral perturbation theory and employs a limited number of free parameters. The achieved description of the photoproduction mass distributions is not quite satisfactory, leaving a room for improving the photo-kernel construction. Although the presented models tend to constrain the positions of the </span><span><math><mi>Λ</mi><mo>(</mo><mn>1405</mn><mo>)</mo></math></span> poles it is difficult to draw any conclusions before accomplishing better data reproduction.</p></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139372877","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":"Role of multi-neutron transfer channels on fusion enhancement","authors":"Simran Rani,&nbsp;Monika Singh,&nbsp;Pardeep Singh","doi":"10.1016/j.nuclphysa.2023.122815","DOIUrl":"10.1016/j.nuclphysa.2023.122815","url":null,"abstract":"<div><p>Fusion reactions ⁴⁰Ar + ¹¹⁶Sn, ⁴⁰Ar + ¹²²Sn and ⁴⁰Ca + ¹²⁴Sn have been examined by employing coupled channel (CC) approach using code-CCFULL. Here we aim to investigate the influence of multi-neutron transfer channels in addition to coupling of collective excitations on sub-barrier fusion enhancement. Incorporation of inelastic excitations alone reproduced the experimental results for ⁴⁰Ar + ¹¹⁶Sn system while for ⁴⁰Ar + ¹²²Sn contribution of 2n transfer channel is required to explain the experimental data. However, CC calculations with 2n transfer could not explain the enhancement at sub-barrier energies for ⁴⁰Ca + ¹²⁴Sn system. Therefore, the empirical coupled channel (ECC) calculations have been carried out to include the effect of multi-neutron transfer channels and it is found that the incorporation of sequential 4n transfer channel reproduced the experimental results in entire energy region. Nevertheless, it is observed that multi-neutron transfer coupling significantly contributed in raising the sub-barrier fusion cross sections particularly for the reactions where colliding partners are spherical. Importantly, it is also found that transfer of even number of neutrons play dominating role in sub-barrier fusion enhancement.</p></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138685007","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":"Quantum entanglement of SO(6)-U(5) transitional nuclei in the interacting boson model-2 (IBM-2)","authors":"M.A. Jafarizadeh ,&nbsp;N. Amiri ,&nbsp;M. Seidi ,&nbsp;M. Ghapanvari","doi":"10.1016/j.nuclphysa.2023.122814","DOIUrl":"10.1016/j.nuclphysa.2023.122814","url":null,"abstract":"<div><p>The quantum shape phase transition between the spherical and deformed <em>γ</em>-unstable (<span><math><mi>U</mi><mo>(</mo><mn>5</mn><mo>)</mo><mo>−</mo><mi>O</mi><mo>(</mo><mn>6</mn><mo>)</mo></math></span>) even-even nuclei within the frameworks of Interacting Boson Model-1 and 2 (IBM-1,2) for low-lying states, using the “entanglement entropy” (S) has been studied. In both frameworks, the theoretical results showed that there exist minimum and maximum entanglement values between s bosons in the U(5) and O(6) limits, respectively. In order to confirmation of the theoretical results, we have calculated and analyzed the entanglement entropy of <span><math><mi>s</mi><mo>−</mo><mi>d</mi></math></span> bosons and proton (<em>π</em>) - neutron (<em>ν</em>) bosons in Cerium (<span><math><mmultiscripts><mrow><mi>C</mi></mrow><mprescripts></mprescripts><mrow><mn>58</mn></mrow><mrow><mn>122</mn><mo>−</mo><mn>136</mn></mrow></mmultiscripts><mi>e</mi></math></span>) isotopes. The results indicate that the entanglement entropy correctly describes the transition from U(5) to O(6), for ground state (<span><math><msubsup><mrow><mn>0</mn></mrow><mrow><mn>1</mn></mrow><mrow><mo>+</mo></mrow></msubsup></math></span>), but it cannot accurately determine the transitional nucleus.</p></div>","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138685046","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":"Relation between degrees of collectivity and repetition patterns of quadrupole transition probabilities in the candidates of shape coexistence","authors":"Asgar Hosseinnezhad,&nbsp;Hadi Sabri","doi":"10.1016/j.nuclphysa.2023.122813","DOIUrl":"10.1016/j.nuclphysa.2023.122813","url":null,"abstract":"<div><p><span>In this article, we study the possible relationship between degrees of freedom of collectivity in protons and neutrons' last orbitals and different patterns of quadrupole<span><span> transition possibilities in the shape coexistence candidates. Because of the dependence of shape coexistence on the arrangement of nucleons in the </span>nuclear structure, we classified the candidates of shape coexistence based on neutrons and protons' last orbitals using the shell-model configuration. In the orbitals corresponding to the neutron numbers in the N=40, 60, and 90 regions, there is a limitation in the degree of freedom for neutrons, and proton-induced shape coexistence occurs. Also, for the orbitals corresponding to the atomic numbers of the Z=40, 52, and 82 regions, the degree of freedom is limited for protons, and neutron-induced coexistence occurs. In this article, we study both the nuclei that belong to the neutron and proton-induced shape coexistence categories and the nuclei that are candidates for shape coexistence but do not belong to the mentioned two categories. The study of different patterns indicates that the </span></span><span><math><mfrac><mrow><mrow><mo>|</mo></mrow><mrow><mi>B</mi><mrow><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>2</mn><mn>2</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup></mrow><mo>)</mo></mrow><mo>−</mo><mi>B</mi><mrow><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup></mrow><mo>)</mo></mrow><mspace></mspace></mrow><mrow><mo>|</mo></mrow></mrow><mrow><mi>B</mi><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup></mrow><mo>)</mo></mrow></mfrac></math></span>, <span><math><mfrac><mrow><mrow><mo>|</mo></mrow><mrow><mi>B</mi><mrow><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>2</mn><mn>2</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup></mrow><mo>)</mo></mrow><mo>−</mo><mi>B</mi><mrow><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>4</mn><mn>1</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup></mrow><mo>)</mo></mrow><mspace></mspace></mrow><mrow><mo>|</mo></mrow></mrow><mrow><mi>B</mi><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>4</mn><mn>1</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup></mrow><mo>)</mo></mrow></mfrac></math></span>, <span><math><mfrac><mrow><mrow><mo>|</mo></mrow><mrow><mi>B</mi><mrow><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>2</mn><mn>2</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><mn>0</mn><mn>1</mn><mo>+</mo></msubsup></mrow><mo>)</mo></mrow><mo>−</mo><mi>B</mi><mrow><mo>(</mo><mrow><mi>E</mi><mn>2</mn><mo>;</mo><msubsup><mn>6</mn><mn>1</mn><mo>+</mo></msubsup><mo>→</mo><msubsup><m","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138608169","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":"Corrigendum to “Peripheral reactions and elastic scattering induced by strongly bound, weakly bound and exotic nuclei” [Nuclear Physics A 1041 (2024) 1–18 122785]","authors":"J.E. Testoni,&nbsp;D. Abriola,&nbsp;G.V. Martí","doi":"10.1016/j.nuclphysa.2023.122804","DOIUrl":"https://doi.org/10.1016/j.nuclphysa.2023.122804","url":null,"abstract":"","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0375947423002087/pdfft?md5=a28c0a50b7e3781567159cec2c8ec42a&pid=1-s2.0-S0375947423002087-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138558916","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":"Imaging constituent quark shape of proton with exclusive vector meson production at HERA","authors":"Wenchang Xiang ,&nbsp;Yanbing Cai ,&nbsp;Daicui Zhou","doi":"10.1016/j.nuclphysa.2023.122810","DOIUrl":"10.1016/j.nuclphysa.2023.122810","url":null,"abstract":"<div><p><span><span>We show within proton hot spot picture that the exclusive vector meson production in electron-proton deeply </span>inelastic scattering is sensitive to the individual width of the constituent quarks of the proton. For comparison, we calculate the exclusive </span><span><math><mi>J</mi><mo>/</mo><mi>Ψ</mi></math></span> production cross-sections in three cases, <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>≥</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span>, <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>&lt;</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>≠</mo><msubsup><mrow><mi>B</mi></mrow><mrow><mi>u</mi></mrow><mrow><mo>′</mo></mrow></msubsup><mo>≠</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span>, where the <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>, <span><math><msubsup><mrow><mi>B</mi></mrow><mrow><mi>u</mi></mrow><mrow><mo>′</mo></mrow></msubsup></math></span> and <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> denote the widths of two up quarks and a down quark. We find that only results calculated with <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>≥</mo><msub><mrow><mi>B</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> can give a reasonable description of the exclusive <span><math><mi>J</mi><mo>/</mo><mi>Ψ</mi></math></span><span> production cross-section data at HERA. To test that our results are independent of the details of the model, we retain the average width of the three constituent quarks unchanged and compute the exclusive </span><span><math><mi>J</mi><mo>/</mo><mi>Ψ</mi></math></span> production cross-sections with contribution weight by setting different proportional coefficients (<span><math><msub><mrow><mi>W</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>W</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span>) for the up and down quarks, respectively. It shows that the results calculated with <span><math><msub><mrow><mi>W</mi></mrow><mrow><mi>u</mi></mrow></msub><mo>≥</mo><msub><mrow><mi>W</mi></mrow><mrow><mi>d</mi></mrow></msub></math></span> can well reproduce the exclusive <span><math><mi>J</mi><mo>/</mo><mi>Ψ</mi></math></span><span> production data at HERA, while the opposite case cannot describe the HERA data. These interesting findings seem to indicate that the up quark has more gluons around it than the down quark at high energy although the spatial distribution of gluons fluctuates event-by-event. To ensure the relevant results independent of the species of the vector meson, we also calculate the </span><em>ρ</em> production cross-sections with the same group of parameters used in the exclusive <span><math><mi>J</mi><m","PeriodicalId":19246,"journal":{"name":"Nuclear Physics A","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138534002","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}