核子结构对质子俘获μ介子的影响

本文指出由于费曼—盖尔曼理论中弱相互作用与电磁相互作用的相似性,矢量耦合部分对质子俘获μ~-介子的贡献与核子的电磁形状因子相联系。本文给出了在重正化的V-A弱作用下质子俘获μ~-介子几率的公式,并根据电子核子散射的实验结果估计了核子的电荷、磁矩分布对μ~-介子俘获几率中矢量耦合部分贡献的修正。     

关于中微子的电磁形状因子的测定

近年来高能电子在核上的散射直接肯定了核子具有一定的结构,实验并已较好地测出了质子和中子的电磁形状因子。但是,轻粒子的形状因子还没有测定。在轻粒子中,中微子的形状因子又是一个很有兴趣的问题。由于中微子只参与弱相互作用,所以对它的结构因子的理论分析可能较为简单。我们在工作中曾经指出,通过和电子(或μ介子)的弱相互作用,中微子将具有一定的电磁形状因子。初看起来,通过中微子v_e在电子上的散射,可以测定中微子的电磁形状因子。但是事实上,因为v_e和电子有一级的弱相互     

核子结构对质子俘获μ- 介子的影响

本文指出由于费曼—盖尔曼理论中弱相互作用与电磁相互作用的相似性,矢量耦合部分对质子俘获μ^-介子的贡献与核子的电磁形状因子相联系。本文给出了在重正化的V-A弱作用下质子俘获μ^-介子几率的公式,并根据电子核子散射的实验结果估计了核子的电荷、磁矩分布对μ^-介子俘获几率中矢量耦合部分贡献的修正。     

核子(质子)奇异性形状因子的实验进展

本文简要地介绍了为测量奇异性海夸克对核子电磁形状因子的贡献的实验的理论基础;详细地介绍了在各个实验室、各个实验时期的实验内容,包括奇异性形状因子的早期测量-MIT Bates设备上SAMPLE组测量奇异性磁形状因子的实验;最近JLab CEBAF设备上HAPPEX合作组对奇异性电和磁形状因子的组合测量;Mainz的MAMI上PVA4实验;HAPPEX的高精度实验及首次单个地测量出奇异性电形状因子;以及JLab的G0组的大接收度、奇异性形状因子对四动量转移平方的依赖关系实验。并介绍了各实验室的不同的实验方法,给出了世界上各实验室在不同的运动学量上的测量的结果,以及进一步可能的实验。     

核子(质子)奇异性形状因子的实验进展

本文简要地介绍了为测量奇异性海夸克对核子电磁形状因子的贡献的实验的理论基础;详细地介绍了在各个实验室、各个实验时期的实验内容,包括奇异性形状因子的早期测量-MIT Bates设备上SAMPLE组测量奇异性磁形状因子的实验;最近JLab CEBAF设备上HAPPEX合作组对奇异性电和磁形状因子的组合测量;Mainz的MAMI上PVA4实验;HAPPEX的高精度实验及首次单个地测量出奇异性电形状因子;以及JLab的G0组的大接收度、奇异性形状因子对四动量转移平方的依赖关系实验.并介绍了各实验室的不同的实验方法,给出了世界上各实验室在不同的运动学量上的测量的结果,以及进一步可能的实验.     

ρ介子Regge极迹与π介子电磁形式因子

π介子电磁形式因子,在光生介子和核子电磁结构等一系列低能π-N系统同电磁场相互作用过程中,起着重要的作用。Frazer和Fulco首先引入并推导出π介子电磁形式因子。由于还没有满意的π-π散射理论,还由于导出的形式因子公式很复杂,不便应用,因此,目前一般都引用唯象或简化了的π介子电磁形式因子。近年来,出现了应用Regge极点方法来导出形式因子的工作。假设ρ介子Regge极点是主要贡献,那么,就     

正负电子湮灭过程的核子激发态N~*产生（英文）

目前,正负电子湮灭过程的核子激发态N~*产生的实验数据主要来自于粲偶素能区。粲偶素衰变到核子激发态过程类似于其类时电磁形状因子测量过程,正反粲夸克短程湮灭提供了近乎于点源的胶子强子化过程。与γN, eN,πN反应互补,这一新的N~*产生源具有同位旋和低自旋筛选的优势。综述了正负电子湮灭过程的核子激发态N~*产生的实验情况和相关的唯象进展,同时讨论未来发展的一些新方向,如正负电子湮灭过程的核子激发态N~*产物的一些新来源等。     

基于微观IBM对电子-核散射及核电磁性质的研究(I) BE理论方案

从价核子自由度出发构造出核跃迁电荷/电流密度算符,采用Dyson玻色子展开技术给出了获取核玻色子形式跃迁电荷/电流密度有效算符的一种微观方法(BE方法).利用微观相互作用玻色子模型(IBM)提供的波函数可在玻色子态空间中求出核跃迁电荷/电流密度,结合电子-核散射以及核电磁跃迁的形式理论,建立了可研究电子-核散射各种形状因子,微分散射截面以及核约化跃迁几率、电磁多极矩、核态g因子等物理量的理论方案.在一种微观sdIBM-2框架下,结合现有理论方案,初步计算了     

赝标介子的唯象模型(Ⅱ) 电磁形状因子

本文直接以平底势计算得到的赝标介子波函数,在欧氏空间中计算出物理的0~-介子的类空电磁形状因子。数值结果表明,在适当选择参数下,理论计算的结果能和实验相符合。     

相对论σ–ω模型中负能海的贡献

在考虑负能海的情况下,运用σ－ω模型,得到了核物质的饱和曲线和好的不可压缩系数,引入形状因子处理了发散积分,仔细研究了ω介子引起的接触相互作用的影响,计算了核基态平均每核子的剩余介子数.     

用高能核子非弹性散射研究核力有效势

本文用扭曲波玻恩近似法及多体高能近似法,处理了原子核对高能核子的非弹性散射现象。在具有可靠的靶核激发态波函数的情况下,可利用这些理论处理方法研究核内两核子间的有效势,本文具体就碳核对185MeV入射核子的非弹性散射进行了计算。在计算中利用了粒子-空穴模型核波函数。在采用了具有各种交换性质并包含自旋轨道耦合项的有效势后,用一组合理的位阱参数,由多体高能近似法计算的理论值可与几个微分截面及极化实验曲线同时符合。     

Contact electromagnetic terms and nuclear shadowing of high-energy photons

The relevance of contact electromagnetic terms in the absorption of photons by nucleons and nuclei is pointed out. A model for computing those terms is presented. Results for the nuclear shadowing of photons are given.     

On the reactions of photoproduction and electromagnetic generation of a and σ hyperons at nucleons near the threshold

The model of current algebra is used to calculate the cross sections of the photoproduction and the electromagnetic generation of strange particles at nucleons near the threshold. It is shown that the existing experimental data are consistent with the predictions of the model.     

A model of weak and electromagnetic interactions of nucleons

Using the concept of spontaneous breakdown of the symmetry in the framework of the Yang-Mills-Higgs-Kibble formalism, the unified model of weak and electromagnetic interactions of point nucleons is suggested.     

Glashow-Weinberg-Salam theory of electroweak interactions and the neutral currents

In the first part of the review we expound in detail the unified theory of weak and electromagnetic interactions of Glashow, Weinberg and Salam. In the second part, on the basis of this theory a number of the neutral current induced processes are discussed. We consider in detail the deep inelastic scattering of neutrinos on nucleons, the P-odd asymmetry in the deep inelastic scattering of longitudinally polarized electrons by nucleons, the scattering of neutrinos on electrons, the elastic scattering of neutrinos on nucleons, and the electron-positron annihilation into leptons.     

Construction of gauge invariant effective nucleonic theories: Functional approach

Starting from relativistic quantum field theories, describing interacting nucleons and pions coupled to the dynamical electromagnetic field, the pion degrees of freedom are eliminated by means of functional integration. Apart from taking into account some operators perturbatively in e, e.g. the vacuum polarization, this procedure is exact, giving effective theories for nucleons and photons. The subsequent nonrelativistic reduction yields the corresponding nonrelativistic quantum field.theory. The latter is unique, irrespective of the precise form of the original nucleon-pion interaction. Nucleonic potentials and electromagnetic interactions are mutually consitent. Local gauge invariance is satisfied at any stage of the formal development.     

Axial form-factor and induced pseudoscalar form-factor of the nucleons

We calculate the axial and the induced pseudoscalar form-factors G_A(t=-Q²) and G_P(t=-Q²) of the nucleons in the framework of the light-cone QCD sum-rules approach up to twist-6 three valence quark light-cone distribution amplitudes, and observe that the form-factors G_A(t=-Q²) and G_P(t=-Q²) at intermediate and large momentum transfers with Q²>2 GeV² have significant contributions from the end-point (soft) terms. The numerical values for the axial form-factor G_A(t=-Q²) are compatible with the experimental data and theoretical calculations; for example, the chiral quark models and lattice QCD. The numerical values for the induced pseudoscalar form-factor G_P(t=-Q²) are compatible with the calculation from the Bethe–Salpeter equation. PACS 12.38.Aw; 12.38.-t; 14.20.Dh     

Sum rules in perturbation theory

Sum rules derived from isospin current algebra are examined in perturbation theory for nucleons interacting with neutral pseudoscalar mesons and isovector pions. It is shown that the well-known sum rules for electromagnetic isovector form factors of nucleons and pions are correct in zero and second order of the meson-nucleon coupling constant.     

The Pion-Recoil Current and Quark-Cluster Effects of Electromagnetic Form Factors of Deuteron

The electromagnetic form factors of deuteron are investigated on hybrid quarkhadron model, whexe meson exchange and six-quark clusters are taken into account. It is found that pion-recoil current and six-quark clusters have important effects on charge form factor, magnetic structure function and tensor polarization, which are all sensitive to the interaction between nucleons. The theoretical predictions agree well with new experimental data.     

Weak and electromagnetic form factors of hadrons

The elastic electromagnetic and weak form factors are studied for nucleons, π and K mesons. Experimental data as well as theoretical approaches are reviewed.