We study the near-threshold pion-induced production ofφmesons off nuclei in the kinematical conditions of the HADES experiment,recently performed at GSI.The calculations have been performed within a collision model b...We study the near-threshold pion-induced production ofφmesons off nuclei in the kinematical conditions of the HADES experiment,recently performed at GSI.The calculations have been performed within a collision model based on the nuclear spectral function.The model accounts for both the primaryπ^-meson–protonπ^-p→φn and the secondary pion–nucleonπN→φNφproduction processes as well as the effects of the nuclearφand nucleon mean-field potentials.We find that the primary reaction channelπ^-p→φn dominates in theφproduction off 12C and^（184）W target nuclei in the HADES acceptance window at incident pion momentum of 1.7 Ge V/c.We calculate the momentum dependence of the absolute and relative（transparency ratio）φmeson yields from the above direct channel.The calculations have been performed for this initial pion momentum allowing for different options for theφN absorption cross sectionσ（φN ）and different scenarios for the in-medium mass shifts of theφmeson and secondary neutron,produced together withφin this channel.We demonstrate that the transparency ratio for theφmesons has,contrary to the absolute cross sections,an insignificant sensitivity to theφmeson and secondary neutron in-medium mass shifts atφmomenta studied in the HADES experiment.On the other hand,we show that there are measurable changes in the transparency ratio due to theφN absorption cross section,which means that such a relative observable can be useful to help determine this cross section from the data taken in the HADES experiment.展开更多
A hybrid star with a pure quark core,a hadron crust and a mixed phase between the two is considered.The relativistic mean field model for hadron matter and the effective mass bag model for quark matter are used to con...A hybrid star with a pure quark core,a hadron crust and a mixed phase between the two is considered.The relativistic mean field model for hadron matter and the effective mass bag model for quark matter are used to construct the equation of state for hybrid stars.The influences of medium effects that are parameterized by the strong coupling constant have been discussed on the configuration of rotating stars.The strong coupling constant is a prominent factor that influences the properties of rotating hybrid stars.展开更多
We study ΛK~＋ pair production in the interaction of protons of 2.83 GeV kinetic energy with C, Cu,Ag, and Au target nuclei in the framework of the nuclear spectral function approach for incoherent primary proton–nu...We study ΛK~＋ pair production in the interaction of protons of 2.83 GeV kinetic energy with C, Cu,Ag, and Au target nuclei in the framework of the nuclear spectral function approach for incoherent primary proton–nucleon and secondary pion–nucleon production processes, and processes associated with the creation of intermediate Σ~0K~＋ pairs. The approach accounts for the initial proton and final Λ hyperon absorption, final K~＋ meson distortion in nuclei, target nucleon binding, and Fermi motion, as well as nuclear mean-field potential effects on these processes.We calculate the Λ momentum dependence of the absolute ΛK~＋ yield from the target nuclei considered, in the kinematical conditions of the ANKE experiment, performed at COSY, within the different scenarios for the Λ-nucleus effective scalar potential. We show that the above observable is appreciably sensitive to this potential in the low-momentum region. Therefore, direct comparison of the results of our calculations with the data from the ANKE-at-COSY experiment can help to determine the above potential at finite momenta. We also demonstrate that the two-step pion–nucleon production channels dominate in the low-momentum ΛK~＋ production in the chosen kinematics and, therefore, they have to be taken into account in the analysis of these data.展开更多
The dynamics of the η meson produced in proton-induced nuclear reactions via the decay of N*(1535)has been investigated within the Lanzhou quantum molecular dynamics transport model.The in-medium modifications of the...The dynamics of the η meson produced in proton-induced nuclear reactions via the decay of N*(1535)has been investigated within the Lanzhou quantum molecular dynamics transport model.The in-medium modifications of the η production in dense nuclear matter are included in the model,in which an attractive η-nucleon potential is implemented.The impact of the η optical potential on the η dynamics is investigated.It is found that the attractive potential leads to the reduction in high-momentum(kinetic energy) production from the spectra of momentum distributions and inclusive cross sections and increasing the reabsorption process by surrounding nucleons.展开更多
核子(质子和中子的总称)大约占宇宙中可见物质总质量的99%.作为构成宇宙可见物质中的最主要成分,核子也是研究强相互作用,尤其是禁闭区非微扰QCD的重要实验室.电子离子对撞机(Electron Ion Collider, EIC),被称作当代卢瑟福散射实验,是...核子(质子和中子的总称)大约占宇宙中可见物质总质量的99%.作为构成宇宙可见物质中的最主要成分,核子也是研究强相互作用,尤其是禁闭区非微扰QCD的重要实验室.电子离子对撞机(Electron Ion Collider, EIC),被称作当代卢瑟福散射实验,是人类认识物质世界深层次结构,特别是核子与原子核结构的理想工具.中国极化电子离子对撞机项目设想在已开建的HIAF高能离子束的基础上升级建造中国电子-离子对撞机(EIC in China,EicC),为我国核物理与粒子物理以及相关科学领域提供大型综合实验平台.本文综述了EicC在核子内不同味道海夸克的一维自旋味道结构、横动量依赖部分子分布函数、广义部分子分布函数测量的理论和模拟研究,展示了EicC在以上测量中可达到的预期精度,以及与现有测量精度的对比.另外,本文也综述了EicC在质子质量起源、重味强子谱、核介质效应及π介子的内部结构等重要物理问题中的潜在贡献,以及EicC探测器概念设计.EicC装置将有力地促进人们对核子自旋和质量的起源、夸克胶子禁闭机制等基本问题的理解.展开更多
文摘We study the near-threshold pion-induced production ofφmesons off nuclei in the kinematical conditions of the HADES experiment,recently performed at GSI.The calculations have been performed within a collision model based on the nuclear spectral function.The model accounts for both the primaryπ^-meson–protonπ^-p→φn and the secondary pion–nucleonπN→φNφproduction processes as well as the effects of the nuclearφand nucleon mean-field potentials.We find that the primary reaction channelπ^-p→φn dominates in theφproduction off 12C and^（184）W target nuclei in the HADES acceptance window at incident pion momentum of 1.7 Ge V/c.We calculate the momentum dependence of the absolute and relative（transparency ratio）φmeson yields from the above direct channel.The calculations have been performed for this initial pion momentum allowing for different options for theφN absorption cross sectionσ（φN ）and different scenarios for the in-medium mass shifts of theφmeson and secondary neutron,produced together withφin this channel.We demonstrate that the transparency ratio for theφmesons has,contrary to the absolute cross sections,an insignificant sensitivity to theφmeson and secondary neutron in-medium mass shifts atφmomenta studied in the HADES experiment.On the other hand,we show that there are measurable changes in the transparency ratio due to theφN absorption cross section,which means that such a relative observable can be useful to help determine this cross section from the data taken in the HADES experiment.
基金Supported by National Natural Science foundation of China (10747126)National Basic Research Program of China (973 Program 2009CB824800)
文摘A hybrid star with a pure quark core,a hadron crust and a mixed phase between the two is considered.The relativistic mean field model for hadron matter and the effective mass bag model for quark matter are used to construct the equation of state for hybrid stars.The influences of medium effects that are parameterized by the strong coupling constant have been discussed on the configuration of rotating stars.The strong coupling constant is a prominent factor that influences the properties of rotating hybrid stars.
基金Supported by the Ministry of Education and Science of the Russian Federation
文摘We study ΛK~＋ pair production in the interaction of protons of 2.83 GeV kinetic energy with C, Cu,Ag, and Au target nuclei in the framework of the nuclear spectral function approach for incoherent primary proton–nucleon and secondary pion–nucleon production processes, and processes associated with the creation of intermediate Σ~0K~＋ pairs. The approach accounts for the initial proton and final Λ hyperon absorption, final K~＋ meson distortion in nuclei, target nucleon binding, and Fermi motion, as well as nuclear mean-field potential effects on these processes.We calculate the Λ momentum dependence of the absolute ΛK~＋ yield from the target nuclei considered, in the kinematical conditions of the ANKE experiment, performed at COSY, within the different scenarios for the Λ-nucleus effective scalar potential. We show that the above observable is appreciably sensitive to this potential in the low-momentum region. Therefore, direct comparison of the results of our calculations with the data from the ANKE-at-COSY experiment can help to determine the above potential at finite momenta. We also demonstrate that the two-step pion–nucleon production channels dominate in the low-momentum ΛK~＋ production in the chosen kinematics and, therefore, they have to be taken into account in the analysis of these data.
基金supported by the Major State Basic Research Development Program in China(No.2014CB845405)the National Natural Science Foundation of China Projects(Nos.11175218,U1332207 and U1432247)the Youth Innovation Promotion Association of Chinese Academy of Sciences,and the Scientific Research Program of Shanxi Provincial Education Department(No.14JK1794)
文摘The dynamics of the η meson produced in proton-induced nuclear reactions via the decay of N*(1535)has been investigated within the Lanzhou quantum molecular dynamics transport model.The in-medium modifications of the η production in dense nuclear matter are included in the model,in which an attractive η-nucleon potential is implemented.The impact of the η optical potential on the η dynamics is investigated.It is found that the attractive potential leads to the reduction in high-momentum(kinetic energy) production from the spectra of momentum distributions and inclusive cross sections and increasing the reabsorption process by surrounding nucleons.
文摘核子(质子和中子的总称)大约占宇宙中可见物质总质量的99%.作为构成宇宙可见物质中的最主要成分,核子也是研究强相互作用,尤其是禁闭区非微扰QCD的重要实验室.电子离子对撞机(Electron Ion Collider, EIC),被称作当代卢瑟福散射实验,是人类认识物质世界深层次结构,特别是核子与原子核结构的理想工具.中国极化电子离子对撞机项目设想在已开建的HIAF高能离子束的基础上升级建造中国电子-离子对撞机(EIC in China,EicC),为我国核物理与粒子物理以及相关科学领域提供大型综合实验平台.本文综述了EicC在核子内不同味道海夸克的一维自旋味道结构、横动量依赖部分子分布函数、广义部分子分布函数测量的理论和模拟研究,展示了EicC在以上测量中可达到的预期精度,以及与现有测量精度的对比.另外,本文也综述了EicC在质子质量起源、重味强子谱、核介质效应及π介子的内部结构等重要物理问题中的潜在贡献,以及EicC探测器概念设计.EicC装置将有力地促进人们对核子自旋和质量的起源、夸克胶子禁闭机制等基本问题的理解.
