20.5 夸口

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  夸口

  

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  The first suggestion of the existence of quarks was presented in 1964 by Murray Gell-Mann and George Zweig. They suggested that protons and neutrons were composed of three quarks called up (u), down (d), and strange (s). A fourth quark was hypothesized just for reasons of symmetry and the name “charm” was suggested for the fourth quark by Sheldon Glashow and James Bkorken. The first evidence for quarks was produced by an experiment in the Stanford Linear Accelerator by James Bkorken and Richard Feynman in 1968. In 1974, Burton Richter and Samuel Ting, separately, announce on the same day that they discovered the same new particle. Ting and his collaborators at Brookhaven called this particle the “J” particle, whereas Richter and his collaborators at SLAC called this particle the psi particle. Since the discoveries are given equal , the particle is commonly known as the J/psi particle. The J/psi particle is a charm-anti-charm meson. After eighteen years of searching at many accelerators, experiments at Fermilab in 1995 discovered the top quark.
  ::1964年,Murray Gell-Mann和George Zweig首次提出夸克存在的第一个建议。他们建议质子和中子由三夸克组成(u, down(d)和s(s)),第四夸克出于对称原因被假设为大小,第四夸克的名称是“魅力”由Sheldon Glasshow和James Bkorken提出,关于夸克的第一个证据是由1968年James Bkorken和Richard Feynman在斯坦福线性加速器中进行的一项实验产生的。1974年,Burton Richter和Samuel Ting分别宣布它们发现了同样的粒子。Ting及其在Brookhaven的同僚者称这一粒子为“J”粒子,而Richter及其在SLAC的同僚称这个粒子为psi粒子。由于发现相同,因此该粒子通常被称为J/psi粒子。J/psi粒子是1995年在Ferclerlerker的顶级实验18年后在Ferclab 中发现的。

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  Quarks
  
  ::夸口

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  When the atomic theory was first suggested, the atoms were considered to be indivisible. Sometime later, it was determined that, in fact, atoms were not indivisible but had component parts, namely protons, neutrons, and electrons. At the time those particles were hypothesized, they were considered to be indivisible, having no smaller parts. In 1964, it was first suggested that protons and neutrons do have smaller component parts, namely quarks . The quark model was accepted very slowly because quarks had not been observed and weren’t all observed until 1995. The known quarks are divided into three families, low , medium energy, and high energy.
  ::当原子理论首次被提出时,原子被认为是不可分割的。 后来,人们确定原子事实上不是不可分割的,而是各组成部分,即质子、中子和电子。 当这些粒子被假定大小时,这些粒子被认为是不可分割的,没有小部分。 1964年,人们首次建议质子和中子确实有较小的组成部分,即夸克。 夸克模型之所以被缓慢地接受,是因为夸克没有被观察到,直到1995年才全部被观察到。 已知的夸克被分为三组,低、中能和高能。

  Quark Name	Symbol	Charge	Family
  Up	u	$\begin{array}{r}+\frac{2}{3}\end{array}$	Low energy family
  Down	d	$\begin{array}{r}-\frac{1}{3}\end{array}$	Low energy family
  Strange	s	$\begin{array}{r}-\frac{1}{3}\end{array}$	Medium energy family
  Charm	c	$\begin{array}{r}+\frac{2}{3}\end{array}$	Medium energy family
  Top	t	$\begin{array}{r}+\frac{2}{3}\end{array}$	High energy family
  Bottom	b	$\begin{array}{r}-\frac{1}{3}\end{array}$	High energy family

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  Particles that are composed of three quarks are called baryons . The two best known baryons are protons and neutrons. A proton is composed of two up quarks and one down quark (uud). The charge on the proton is the result of adding the charges on these quarks $\begin{array}{r}\left(+\frac{2}{3}+\frac{2}{3}-\frac{1}{3}=+1\right)\end{array}$ . Neutrons are composed of one up quark and two down quarks (udd). The charge on the neutron is the result of adding the charges on these quarks $\begin{array}{r}\left(+\frac{2}{3}-\frac{1}{3}-\frac{1}{3}=0\right)\end{array}$ .
  ::由三夸克组成的粒子称为巴伦斯;两个最著名的巴伦斯是质子和中子;一个质子由两个上方的夸克和一个下方的夸克(uud)组成;质子上的电荷是增加这些夸克(+23+23-23-131)的电荷的结果;中子由一个上方的夸克和两个下方的夸克(udd)组成;中子上的电荷是增加这些夸克的电荷的结果(+23-13-13=0)。

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  Everyday objects are made up of quarks from the lowest energy family, namely up and down quarks. Quarks in the middle energy family are found in cosmic rays and are produced in particle accelerators. Particles in the high energy family are believed to have existed briefly during the earliest moments of the Big Bang and are created only in high energy collisions.
  ::每天的物体由来自能源最低的家庭的夸克组成,即上下方的夸克。中等能源家庭的夸克在宇宙射线中发现,并用粒子加速器产生。据信,高能量家庭的粒子在大爆炸的最初时刻短暂存在,只是在高能量碰撞中产生。

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  Launch the simulation below to explore the Subatomic Particle Zoo. Click on the Boson Pond and try to find the gluon, responsible for the strong nuclear force that binds quarks together to make protons and neutrons. Then, travel to the Hadron Forest to observe different combinations of quarks such as mesons and baryons:
  ::启动以下模拟以探索亚原子粒子动物园。 点击 Boson Pond , 并试图找到能让二次核力量结合以制造质子和中子的强大核力量的格伦。 然后, 前往哈德伦森林观察诸如米森和巴龙等不同组合的夸克:

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  Summary
  ::摘要

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  • In 1964, it was first suggested that protons and neutrons do have smaller component parts, namely quarks.
    ::1964年,首次建议质子和中子确实有较小的部件,即夸克。
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  • The known quarks are divided into three families, low energy, medium energy, and high energy.
    ::已知的夸克地区分为三个家庭,即低能、中能和高能三个家庭。
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  • Particles that are composed of three quarks are called baryons.
    ::由三夸克组成的粒子被称为男爵。
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  • A proton is composed of two up quarks and one down quark (uud).
    ::质子由两个上方的夸克和一个下方的夸克组成。
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  • Neutrons are composed of one up quark and two down quarks (udd).
    ::中子由一个上方的夸克和两个下方的夸克组成。

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  Review
  ::回顾

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  1. How many families of quarks are there?
     ::有多少个夸克家庭?
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  2. How many quarks are there and what are their names?
     ::有多少夸克 和他们的名字是什么?
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  3. Which was the last quark found?
     ::最后找到的夸克是哪个?

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  Explore More
  ::探索更多

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  Use this resource to answer the questions that follow.
  ::使用此资源回答下面的问题 。

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  1. Which particle accelerator is mentioned in the video?
     ::视频中提到哪一种粒子加速器?
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  2. How are the families of quarks referred to in the video?
     ::影片中如何提及夸克人的家庭?