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发表于 2005-8-27 21:27:35
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Why do we need the LHC?
为什么我们需要LHC?
Because our current understanding of the Universe is incomplete.
因为我们现在对宇宙的认识还不完整。
The theories and discoveries of thousands of physicists over the past century have created a remarkable picture of the fundamental structure of matter, which is called the Standard Model of Particles and Forces. The Standard Model is by now a well-tested physics theory, used to explain and exactly predict a vast variety of phenomena. High-precision experiments have repeatedly verified
subtle predicted effects. Nevertheless, physicists know that it can't be the end of the story, as it leaves many unsolved questions.
在过去一个世纪中，众多物理学家的理论和发现揭示了粒子与力的标准模型这一个描述物质基本结构的图景。在现在，标准模型已经被广泛验证，并被应用于解释并预言广泛的物理现象。不断重复的精确实验出来的结果与标准模型的预言精确匹配。不过，由于它还留下了很多未解之谜，所以，故事远未完结。
图中分别为：
上夸克 下夸克 电子中微子 电子
粲夸克 奇异夸克 μ子中微子 μ子
顶夸克 底夸克 τ子中微子 τ子
Among them, the reason why elementary particles have mass, and why their are different, is the most perplexing one. It is remarkable that such a familiar
concept is so poorly understood! The answer may lie within the Standard model, in an idea called the Higgs mechanism. According to this, the whole of space is filled with a 'Higgs field', and by interacting with this field, particles acquire their masses. Particles which interact strongly with the Higgs field are heavy, whilst those which interact weakly are light. The Higgs field has at least one new particle associated with it, the Higgs boson. If such particle exists, the LHC will be able to make it detectable.
在这些疑惑当中，最令人困惑的是：为什么基本粒子会有各自不同的质量呢？由于我们对这个如此简单的观念的理解如此的少，所以这个问题实在引人注目。这个问题的答案可能就是标准模型中一个叫“希格斯机制”的思想。根据这个思想，整个空间被一个所谓的“希格斯场”所充满，粒子通过与这个场相互作用而获得质量。与希格斯场相互作用强的质量就大，反之质量就小。这个希格斯场至少联系一个新的粒子，我们叫它西格斯玻色子。如果这样的粒子存在的话，LHC就可以探测到它。
Another puzzle concerns the existence of four different forces. When the Universe was young and much hotter than today, perhaps these forces all behaved as one. Particle physicists hope to find a single theoretical framework to prove this, and have already had some success. Two forces, the electromagnetic force and the weak force were 'unified' into a single theory in the 1970s. This theory was experimentally verified in a Nobel prize winning experiment at CERN a few years later. The weakest and the strongest forces, however, gravity and the strong force, remain apart. A very popular idea suggested by the unification of the forces is called supersymmetry or SUSY for short. SUSY predicts that for each known particle there is a 'supersymmetric' partner. If SUSY is right, then supersymmetric particles should be found at the LHC.
另一个疑问是关于四种力为何存在的。当宇宙诞生不久，还没变冷的时候，可能四种力的行为是一样的。粒子物理学家希望找到一个单一的理论体系来证明它，现在已经有了一定的进展。在19世纪70年代，电磁力和弱力已经被统一为一个单一的理论。几年以后，这个理论被一场在CERN举行的、后来获得诺贝尔奖的实验所证实。但是，四种力中强度最弱的引力和强度最强的强力还是水火不相容。力的统一暗示的一个流行的观点就是超对称（简称SUSY）。超对称预言，每一个已知粒子都有它的超对称“伙伴”。如果超对称是正确的，那么这些超对称粒子应该会在LHC中被找到。
Antimatter poses another riddle the LHC will help us also to solve the riddle of antimatter. It was once thought that antimatter was a perfect 'reflection' of matter - that if you replaced matter with antimatter and looked at the result in a mirror, you would not be able to tell the difference. We now know that the reflection is imperfect, and this could have led to the matter-antimatter imbalance. The LHC will be a very good 'antimatter-mirror', allowing us to put the Standard Model through one of its most grueling tests yet.
反物质给我们出了另一个谜，LHC能够帮助我们解答它。我们曾经一度认为反物质是物质的完美镜像。如果你将物质替换成反物质，然后在镜子中观看结果，你不会察觉与正常的有何不同。现在我们知道，这种镜像是不完美的，这就导致了物质与反物质之间的不平衡。LHC会成为一个很好的“反物质镜子”，能让我们用至今最严酷的实验来检验标准模型。
These are just a few of the questions the LHC should answer, but history has shown that the greatest advances in science are often unexpected. Although we have a good idea of what we hope to find at the LHC, nature may well have
surprises in store.
这只是LHC能够回答的一些问题。历史证明，最伟大的科学进步往往是无法预料的。尽管我们有一个建造LHC的绝佳理由，但自然总是出人意料的。
One thing is certain, the LHC will change our view of the Universe.
有一件事是确定的，就是LHC会改变我们对宇宙的看法
[ Last edited by fwjmath on 2005-8-27 at 21:29 ] |
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发表于 2005-8-27 08:49:38