中介子

The paper is made up of two parts:Firstly, we studied systematically the radiative decays of light vector mesons:〓in the framework of a U(3)L×U(3)〓chiral theory of mesons. In this theory, low-lying pseudo scalar, vector, axial vectormesons are introduced as the bound states of the quark fields.

全文分轻味矢量介子辐射衰变和重味矢量介子的软π衰变两部分：首先，我们在U(3)〓×U(3)〓手征介子理论的框架内，系统的研究了轻味矢量介子ρ，φ的辐射衰变〓在该理论中，低能的赝标，矢量和轴矢介子场是作为夸克场的束缚态被纳入。

At the same time, due to 2~1S_0、 3_1S_0 are the radical excitations of 1~1S_0,we can use Regge trajectory on the (n,M~2)-plane with the approximate same slope to describe the mass of isoscalar of 3~1S_0 nonet (1926MeV). The two results derive from different ways are approximate. 2 The mass of the isodoublet of 2~3S_1 nonet is analyzed in the quarkonium-quarkonium mixing scheme, the results (1584±16.7MeV) is far from the K~*(1410)(1414±15MeV). 3 Based on "glueball dominance" picture, we establish glueball-meson mass relations. For the 2~ glueball mass and 4~ glueball mass used as input parameters, these relations predict the mass of isoscalar of 1~3F_4(4~)(2076±19.66MeV).

的质量(1900±12MeV)；同时考虑到2~1S_0、3~1S_0为1~1S_0的径向激发态，在(n，M~2)雷吉轨迹图中应该具有近似相同的斜率，利用雷吉轨迹可以得到其对应质量为(1926MeV)，两种方法得到了两个十分自洽的结果。2在介子—介子混合框架下，对2~3S_1介子九重态中同位旋二重态的质量给出估计，得到(1584±16.7MeV)，这个结果相对于K~*(1410)=1414±15MeV有较大的偏离。3在胶球为主的图像下，利用介子—胶球质量关系，选择2~与4~胶球的质量作为输入参数，我们得到1~3F_44~(介子九重态中同位旋标量态？

The IQMD model is introduced in detail at first, then shows the production machanism of pions and the generation machanism of concave pion spectra at length.

首先，对 IQMD模型做了介绍，讨论了模型中π介子的产生机制及π介子谱的双玻尔兹曼分布的形成机制。

Among mesons, the lightest and most important one is certainly the pion, thus it is no accident that its structure, properties (both in free space and in nuclear matter) and interactions with nucleons and nuclei have gotten considerable attentions in the past and again at the present time.

在各种介子中，π介子是最轻且最重要的介子，关于自由空间中π介子的结构与性质、核介质内π介子的性质、π-核子相互作用与π-核相互作用等问题，始终受到相当多的关注。

We find the most contributions of form factors come fromΨπ,K andΨB, but the contributions ofΨσfrom the pion and the kaon meson, the contribution ofΔfrom B meson are very small, and can be neglected in most of the calculations.

结果发现π、K介子波函数中的Ψπ，K，B介子波函数中的ΨB对形状因子的贡献最大，而π、K介子波函数中的Ψσ，B介子波函数中的Δ对形状因子的影响很小，可以忽略。

Finally,we discuss the mixing and decays of multi-resonances via studying the properties of the pseudoscalar and scalar mesons.For the pseudoscalar mesons, we find the eta(1410) is mainly a glueball state by studying the decays of the ground pseudoscalar mesons. For the scalar mesons, we suggest the ground mesons contain neglect

对于赝标介子，通过研究它们的衰变发现eta(1410)的主要成分是胶球，对于标量介子，借助描述五个标量介子混合的质量矩阵，通过拟合观察到的标量介子的质量，发现基态标量介子中的胶球成分可以忽略，而其径向激发态中含有比较多的胶球成分。

The contributions ofΨp from the pion and the kaon meson, the contribution ofΨB from B meson are not very small, and can not be safely neglected for giving more resonable results of form factors.The B meson wavefunction is a major source of uncertainty in the study of B meson decays. The B→πand B→K transition form factors provide a good platform to determine the possible regions for the two typical phenomenological parametersΛandδ.

但π、K介子波函数中的Ψp和B介子波函数中的ΨB对形状因子的贡献比较大，为了获得更加合理的形状因子的结果，一般不能忽略π、K介子波函数中的Ψp和B介子波函数中的ΨB项的贡献。B介子波函数是B介子衰变中不确定性的一个主要的来源。B→π和B→K跃迁形状因子为确定两个典型的唯象参数Λ和δ提供了一个很好的平台。

A possible quantum mechanical picture of multiple production of mesons is discussed in the present paper.

本文讨论在宇宙射线中介子簇射产生的一种可能的过程。

This is a fairly critical part of the apparatus, which catches the pions and confines some of them into a beam while they decay into muons.

这是用具的一个相当重要零件，捉住中介子和限制有些入射线当他们腐朽入muons 。

You are simulating the part of the process where the protons hit a target rod and cause pions to be emitted, which decay into muons, which then proceed to a storage ring and decay into electrons and neutrinos.

您模仿氢核击中一把目标标尺和导致中介子散发，腐朽入muons ，然后进行对存贮圆环和朽烂入电子和中微子过程的部份。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。