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
Medium polarization eflects are studied for 1S0 pairing in nuclear matter within BHF approach. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instabili...Medium polarization eflects are studied for 1S0 pairing in nuclear matter within BHF approach. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. The self-energy effects always lead to a quenching of the gap, whereas it is almost completely compensated by the anti-screening effect in nuclear matter.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
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 NSFC (10875150)the grant appointed to European Community Project Asia-Europe Link in Nuclear Physics and Astrophysics, CN/ASIA-LINK/008(94791)
文摘Medium polarization eflects are studied for 1S0 pairing in nuclear matter within BHF approach. The screening potential is calculated in the RPA limit, suitably renormalized to cure the low density mechanical instability of nuclear matter. The self-energy corrections are consistently included resulting in a strong depletion of the Fermi surface. The self-energy effects always lead to a quenching of the gap, whereas it is almost completely compensated by the anti-screening effect in nuclear matter.
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.
