Numerous experimental and theoretical investigations have highlighted the power law behavior of the proton structure function F_(2)(x,Q^(2)),particularly the dependence of its power constant on various kinematic varia...Numerous experimental and theoretical investigations have highlighted the power law behavior of the proton structure function F_(2)(x,Q^(2)),particularly the dependence of its power constant on various kinematic variables.In this study,we analyze the proton structure function F_(2)employing the analytical solution of the Balitsky–Kovchegov equation,with a focus on the high Q^(2)regime and small x domains.Our results indicate that as Q^(2)increases,the slope parameterλ,which characterizes the growth rate of F_(2),exhibits a gradual decrease,approaching a limiting value ofλ≈0.41±0.01 for large Q^(2).We suggest that this behavior ofλmay be attributed to mechanisms such as gluon overlap and the suppression of phase space growth.To substantiate these conclusions,further high-precision electron–ion collision experiments are required,encompassing a broad range of Q^(2)and x.展开更多
We present a comprehensive analysis of near-threshold photoproduction ofρ^(0),ω,andΦmesons on a deuterium target,utilizing published datasets from DESY and SLAC forρ^(0)andωproduction,as well as data from the LEP...We present a comprehensive analysis of near-threshold photoproduction ofρ^(0),ω,andΦmesons on a deuterium target,utilizing published datasets from DESY and SLAC forρ^(0)andωproduction,as well as data from the LEPS and CLAS Collaborations forΦproduction.In extracting the deuteron mass radius,we adopt a dipole parameterization for the scalar gravitational form factor,which effectively captures the|t|-dependence of the differential cross sections associated with vector meson photoproduction.In addition,results from alternative commonly used form factor parameterizations are considered and compared.By employing the vector meson dominance(VMD)framework and invoking low-energy Quantum Chromodynamics(QCD)theorems,we extract the deuteron mass radius from near-threshold photoproduction data ofρ^(0),ω,andΦmesons.The mass radii obtained from the various datasets are found to be consistent within statistical uncertainties,yielding an average value of 2.03±0.13 fm under the dipole form assumption.We also provide a detailed discussion of the sensitivity of the extracted radius to the choice of gravitational form factor models.Our result represents a significant improvement in precision compared to earlier estimates based solely onΦmeson photoproduction,offering new constraints for theoretical models of nuclear structure and deepening our understanding of the mass distribution within the deuteron.展开更多
Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei.As a future high energy nuclear physics project,an Electron-ion collider in China(EicC)...Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei.As a future high energy nuclear physics project,an Electron-ion collider in China(EicC)has been proposed.It will be constructed based on an upgraded heavy-ion accelerator,High Intensity heavy-ion Accelerator Facility(HIAF)which is currently under construction,together with a new electron ring.The proposed collider will provide highly polarized electrons(with a po-larization of 80%)and protons(with a polarization of 70%)with variable center of mass energies from 15 to 20 GeV and the luminosity of(2–3)×1033 cm^(−2)·s^(−1).Polarized deuterons and Helium-3,as well as unpolarized ion beams from Carbon to Uranium,will be also available at the EicC.The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region,including 3D tomography of nucleon;the partonic structure of nuclei and the parton interaction with the nuclear environment;the exotic states,especially those with heavy flavor quark contents.In addition,issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC.In order to achieve the above-mentioned physics goals,a hermetical detector system will be constructed with cutting-edge technologies.This document is the result of collective contributions and valuable inputs from experts across the globe.The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States.The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China.展开更多
Measuring the kaon structure beyond proton and pion structures is a prominent topic in hadron physics,as it is one way to understand the nature of the Nambu-Goldstone boson of QCD and observe the interplay between the...Measuring the kaon structure beyond proton and pion structures is a prominent topic in hadron physics,as it is one way to understand the nature of the Nambu-Goldstone boson of QCD and observe the interplay between the EHM and HB mechanisms for hadron mass generation.In this study,we present a simulation of the leading A baryon tagged deep inelastic scattering experiment at EicC(Electron-ion collider in China),which is engaged to unveil the internal structure of kaon via the Sullivan process.According to our simulation results,the suggested experiment will cover the kinematical domain of 0.05≤xK≤0.85 and Q^(2)up to 50 GeV^(2),with the acceptable statistical uncertainties.In the relatively low-Q^(2) region(<10 GeV^(2)),the Monte-Carlo simulation shows a good statistical precision(<5%)for the measurement of the kaon structure function F2K.In the high-Q^(2) region(up to 50 GeV^(2)),the statistical uncertainty of F_(2)^(K) is also acceptable(<10%)for the data at xK<0.8.To perform such an experiment at an electron-ion collider,a high-performance zero-degree calorimeter is suggested.The magnitude of the background process and the assumed detector capabilities are also discussed and illustrated in the paper.展开更多
A new method to test the valence quark distribution of nucleons obtained from the maximum entropy method using the Gottfried sum rule by performing the DGLAP equations with GLR-MQ-ZRS corrections and the original lead...A new method to test the valence quark distribution of nucleons obtained from the maximum entropy method using the Gottfried sum rule by performing the DGLAP equations with GLR-MQ-ZRS corrections and the original leading-order/next-to-leading-order （LO/NLO） DGLAP equations is outlined. The test relies on knowledge of the unpolarized electron proton structure function F2^ep and the electron neutron structure function F2^en and the assumption that Bjorken scaling is satisfied. In this work, the original Gottfried summation value obtained by the integrals of the structure function at different Q2 is in accordance with the theoretical value of 1/3 under the premise of light-quark flavor symmetry of the nucleon sea, whether it results from dynamical evolution equations or from global quantum chromodynamics fits of PDFs. Finally, we present the summation value of the LO/NLO DGLAP global fits of PDFs under the premise of light-quark flavor asymmetry of the nucleon sea. According to analysis of the original Gottfried summation value with two evolution equations at different Q2 we find that the valence quark distributions of nucleons obtained by using the maximum entropy method are effective and reliable.展开更多
基金supported by the National Key R&D Program of China(Grant Nos.2024YFE0109800 and 2024YFE0109802)the National Natural Science Foundation of China(Grant No.12305127)the International Partnership Program of the Chinese Academy of Sciences(Grant No.016GJHZ2022054FN)。
文摘Numerous experimental and theoretical investigations have highlighted the power law behavior of the proton structure function F_(2)(x,Q^(2)),particularly the dependence of its power constant on various kinematic variables.In this study,we analyze the proton structure function F_(2)employing the analytical solution of the Balitsky–Kovchegov equation,with a focus on the high Q^(2)regime and small x domains.Our results indicate that as Q^(2)increases,the slope parameterλ,which characterizes the growth rate of F_(2),exhibits a gradual decrease,approaching a limiting value ofλ≈0.41±0.01 for large Q^(2).We suggest that this behavior ofλmay be attributed to mechanisms such as gluon overlap and the suppression of phase space growth.To substantiate these conclusions,further high-precision electron–ion collision experiments are required,encompassing a broad range of Q^(2)and x.
基金Supported by the National Natural Science Foundation of China(12305127)the International Partnership Program of the Chinese Academy of Sciences(016GJHZ2022054FN)National Key R&D Program of China(2024YFE0109800,2024YFE0109802)。
文摘We present a comprehensive analysis of near-threshold photoproduction ofρ^(0),ω,andΦmesons on a deuterium target,utilizing published datasets from DESY and SLAC forρ^(0)andωproduction,as well as data from the LEPS and CLAS Collaborations forΦproduction.In extracting the deuteron mass radius,we adopt a dipole parameterization for the scalar gravitational form factor,which effectively captures the|t|-dependence of the differential cross sections associated with vector meson photoproduction.In addition,results from alternative commonly used form factor parameterizations are considered and compared.By employing the vector meson dominance(VMD)framework and invoking low-energy Quantum Chromodynamics(QCD)theorems,we extract the deuteron mass radius from near-threshold photoproduction data ofρ^(0),ω,andΦmesons.The mass radii obtained from the various datasets are found to be consistent within statistical uncertainties,yielding an average value of 2.03±0.13 fm under the dipole form assumption.We also provide a detailed discussion of the sensitivity of the extracted radius to the choice of gravitational form factor models.Our result represents a significant improvement in precision compared to earlier estimates based solely onΦmeson photoproduction,offering new constraints for theoretical models of nuclear structure and deepening our understanding of the mass distribution within the deuteron.
文摘Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei.As a future high energy nuclear physics project,an Electron-ion collider in China(EicC)has been proposed.It will be constructed based on an upgraded heavy-ion accelerator,High Intensity heavy-ion Accelerator Facility(HIAF)which is currently under construction,together with a new electron ring.The proposed collider will provide highly polarized electrons(with a po-larization of 80%)and protons(with a polarization of 70%)with variable center of mass energies from 15 to 20 GeV and the luminosity of(2–3)×1033 cm^(−2)·s^(−1).Polarized deuterons and Helium-3,as well as unpolarized ion beams from Carbon to Uranium,will be also available at the EicC.The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region,including 3D tomography of nucleon;the partonic structure of nuclei and the parton interaction with the nuclear environment;the exotic states,especially those with heavy flavor quark contents.In addition,issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC.In order to achieve the above-mentioned physics goals,a hermetical detector system will be constructed with cutting-edge technologies.This document is the result of collective contributions and valuable inputs from experts across the globe.The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States.The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34030301)the National Natural Science Foundation of China(12005266)the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030008)。
文摘Measuring the kaon structure beyond proton and pion structures is a prominent topic in hadron physics,as it is one way to understand the nature of the Nambu-Goldstone boson of QCD and observe the interplay between the EHM and HB mechanisms for hadron mass generation.In this study,we present a simulation of the leading A baryon tagged deep inelastic scattering experiment at EicC(Electron-ion collider in China),which is engaged to unveil the internal structure of kaon via the Sullivan process.According to our simulation results,the suggested experiment will cover the kinematical domain of 0.05≤xK≤0.85 and Q^(2)up to 50 GeV^(2),with the acceptable statistical uncertainties.In the relatively low-Q^(2) region(<10 GeV^(2)),the Monte-Carlo simulation shows a good statistical precision(<5%)for the measurement of the kaon structure function F2K.In the high-Q^(2) region(up to 50 GeV^(2)),the statistical uncertainty of F_(2)^(K) is also acceptable(<10%)for the data at xK<0.8.To perform such an experiment at an electron-ion collider,a high-performance zero-degree calorimeter is suggested.The magnitude of the background process and the assumed detector capabilities are also discussed and illustrated in the paper.
基金Supported by National Basic Research Program of China(973 Program)(2014CB845406)
文摘A new method to test the valence quark distribution of nucleons obtained from the maximum entropy method using the Gottfried sum rule by performing the DGLAP equations with GLR-MQ-ZRS corrections and the original leading-order/next-to-leading-order （LO/NLO） DGLAP equations is outlined. The test relies on knowledge of the unpolarized electron proton structure function F2^ep and the electron neutron structure function F2^en and the assumption that Bjorken scaling is satisfied. In this work, the original Gottfried summation value obtained by the integrals of the structure function at different Q2 is in accordance with the theoretical value of 1/3 under the premise of light-quark flavor symmetry of the nucleon sea, whether it results from dynamical evolution equations or from global quantum chromodynamics fits of PDFs. Finally, we present the summation value of the LO/NLO DGLAP global fits of PDFs under the premise of light-quark flavor asymmetry of the nucleon sea. According to analysis of the original Gottfried summation value with two evolution equations at different Q2 we find that the valence quark distributions of nucleons obtained by using the maximum entropy method are effective and reliable.
