String cloud and domain walls with quark matter for a higher dimensional FRW universe in self creation cosmology

In this study, we research a higher dimensional flat Friedmann-Robertson-Walker(FRW) universe in Barber's second theory when strange quark matter(SQM) and normal matter(NM) are attached to the string cloud and domain walls. We obtain zero string tension density for this model. We obtain dust quark matter solutions. This result agrees with Kiran and Reddy, Krori et al, Sahoo and Mishra and Reddy. In our solutions the quark matter transforms to other particles over time. We also obtain two different solutions for domain walls with quark and normal matters by using a deceleration parameter. Also, the features of the obtained solutions are discussed and some physical and kinematical quantities are generalized and discussed. Our results are consistent with Yilmaz, Adcox et al and Back et al in four and five dimensions.     

Meson decays in an extended Nambu—Jona-Lasinio model with heavy quark flavors

In a previous work,we proposed an extended Nambu-Jona-Lasinio(NJL)model including heavy quark flavors.In this work,we will calculate strong and radiative decays of vector mesons in this extended NJL model,including lightρ,ω,K*,(?)and heavy D~*,D_s~*,B~*,B_s~*.     

探索物质微观结构的历史回顾——纪念夸克提出50周年

1964年盖尔曼和兹威格分别提出"基本粒子"由夸克或艾斯组成。至今,这一领域仍是粒子物理研究的前沿领域。经过50年的发展,夸克(艾斯)理论取得诸多辉煌成就。文章简要地回顾了夸克的提出过程及随后实验和理论方面的进展。     

在同位旋空间中正反质子弹性散射的重整化混合圈链图效应

本文采用描述荷电和中性 pion 介子与核子-反核子强相互作用的同位旋SU(2)不变耦合模型,计算出在 pion0 重整化混合圈链图传播下 p pbar -> p pbar 弹性散射微分截面的“精确”解析结果;并且将此结果与在 pion0 树图传播下的微分截面作了对比分析,得到相应的辐射修正重要信息。本文完成的工作对进一步深入研究 pion 介子与核子-反核子强相互作用的同位旋SU(2)不变耦合模型以及深入理论探讨正反质子对撞实验,都将提供理论研究的参考价值。     

在同位旋SU(2)不变耦合模型中研究 p pbar -> n nbar 核子反应的重整化无穷阶链图效应

本文采用描述中性及荷电 pion 介子（pion0,pion+,pion-）与核子-反核子强相互作用的同位旋SU(2)不变耦合模型,计算出在pion0 及 pion+, pion- 重整化链图传播下 p pbar -> n nbar 核子反应微分截面的“精确”解析结果;并且将此结果与在 pion0 及 pion+, pion- 树图传播下的微分截面作了对比分析,得到相应的辐射修正重要信息。本文完成的工作对进一步深入研究三种荷电状态 pion 介子与核子-反核子强相互作用的同位旋SU(2)不变耦合模型以及深入理论探讨质子-反质子对撞实验,都将提供某些理论研究的参考价值。     

Phase structures of neutral dense quark matter and applicationto strange stars

In the contact interaction model,the quark propagator has only one solution,namely,the chiral symmetry breaking solution,at vanishing temperature and density in the case of physical quark mass.We generalize the condensate feedback onto the coupling strength from the 2 flavor case to the 2+1 flavor case,and find the Wigner solution appears in some regions,which enables us to tackle chiral phase transition as two-phase coexistences.At finite chemical potential,we analyze the chiral phase transition in the conditions of electric charge neutrality andβequilibrium.The four chemical potentials,μ_u,μ_d,μ_s and He,are constrained by three conditions,so that one inde-pendent variable remains:we choose the average quark chemical potential as the free variable.All quark masses and number densities suffer discontinuities at the phase transition point.The strange quarks appear after the phase trans-ition since the system needg more energy to produce a d.-quark than an s-quark.Taking the EOS as an input,the TOV equations are solved numerically,and we show that the mass--radius relation is sensitive to the EOS.The max-imum mass of strange quark stars is not susceptible to the parameter Aq we introduced.     

Landau quantization and spin polarization of cold magnetized quark matter

The magnetic field and density behaviors of various thermodynamic quantities of strange quark matter under compact star conditions are investigated in the framework of the thermodynamically self-consistent quasiparticle model. For individual species, a larger number density \begin{document}$ n_i $\end{document} leads to a larger magnetic field strength threshold that aligns all particles parallel or antiparallel to the magnetic field. Accordingly, in contrast to the finite baryon density effect which reduces the spin polarization of magnetized strange quark matter, the magnetic field effect leads to an enhancement of it. We also compute the sound velocity as a function of the baryon density and find the sound velocity shows an obvious oscillation with increasing density. Except for the oscillation, the sound velocity grows with increasing density, similar to the zero-magnetic field case, and approaches the conformal limit \begin{document}$ V_s^2=1/3 $\end{document} at high densities from below.     

核子白旋结构的实验研究进展

本文主要介绍对核子纵向自旋结构函数的实验研究进展。首先简要介绍核子自旋结构的部分理论模型,包括朴素的部份子模型和QCD中的夸克一部份子模型,同时简要介绍标度律和标度律的破坏及其原因;接着介绍实验研究的理论基础,包括弱作用和轻子一核子的深度非弹散射中轴流的作用和几个关于核子自旋结构的求和规则和它们的QCD修正;且简要介绍深度非弹散射实验的研究方法,包括单举测量、半单举和遍举测量。最后,详细介绍实验研究进展,包括对质子和。中子的纵向自旋结构函数的测量,国际上几个主要实验室在不同的能量下,在用不同的靶、不同的束流对不同范围的Bjorken变量x和不同的四动量转移范围Q2下的实验、特点及其结果。最后简略介绍了我国实验物理工作者在该领域的国际合作组的部分工作。     

Study of the heavy molecular states in the quark model with meson exchange interaction

Some charmonium-like resonances such as X(3872) can be interpreted as possible D^(*)D^(*) molecular states. Within the quark model, we study the structure of such molecular states and the similar B^(*)D^(*) molecular states by taking into account the light meson exchange (π, η, ρ, ω and σ) between two light quarks from different mesons.