What is dark matter? Or gravity? Why is the universe so smooth? There's a particle for every conundrum

什么是暗物质？什么是引力？为什么宇宙如此平滑？每一个难题就会有一个新的粒子

WHEN, in the late 1930s, the Nobel laureate Isidor Rabi learned of the discovery of a heavier version of the electron, he asked "Who ordered that?". Three-quarters of a century on, he could repeat that question many times over. We now know that Rabi's intruder, the muon, is one of a family of three electron-like particles that differ only in their mass.

在20世纪30年代后期，诺贝尔物理学奖获得者Isidor Rabi了解到较重版本的电子的发现，他问："是谁订的？"。四分之三个世纪以来，同样的问题可以问很多次。我们现在知道，Rabi的不速之客，μ轻子，是类似电子的粒子家族的三者之一，区别仅在于它们的质量。

It doesn't end there. What is called the standard model of matter and its interactions relies on a panoply of particles, some familiar, some less familiar (see diagram). The Large Hadron Collider (LHC), which this month is preparing to smash protons together at CERN near Geneva, Switzerland, for its third full season, is looking for the definitive trace of the only particle predicted by the standard model still to be discovered - the Higgs boson, giver of mass.

这还没有结束。物质及其相互作用的标准模型依赖于一套粒子体系，有的为人们熟悉的，有的则不熟悉。在第三季度还在准备粉碎质子的瑞士日内瓦附近的欧洲核子研究中心的大型强子对撞机（LHC），是寻找标准模型预言的希格斯玻色子——质量的赋予者——唯一的权威。

And much more besides. The standard model leaves many questions unanswered. Why does matter dominate antimatter in our cosmos? What is the true nature of gravity? What is the "dark matter" that appears to hold galaxies together made of? Attempts to answer such questions lead physicists time and time again to the same expedient: invent a new particle.

但还有许多标准模型留下的悬而未决的问题。为什么我们宇宙中的物质远超过反物质？什么是引力的本质？什么是把星系拉在一起的"暗物质"？试图回答这样的问题导致物理学家一次又一次采用相似的权宜之计：发明一种新的粒子。

• differ [´difə]   vi.不同；有差别   (初中英语单词)
• invent [in´vent]   vt.发明；捏造   (初中英语单词)
• gravity [´græviti]   n.严肃；严重；重力   (高中英语单词)
• universe [´ju:nivə:s]   n.天地；全人类；银河系   (高中英语单词)
• particle [´pɑ:tikl]   n.微粒；极小量   (高中英语单词)
• learned [´lə:nid]   a.有学问的，博学的   (高中英语单词)
• geneva [dʒi´ni:və]   n.日内瓦   (高中英语单词)
• switzerland [´switsələnd]   n.瑞士   (高中英语单词)
• dominate [´dɔmineit]   v.统治；控制；俯视   (高中英语单词)
• version [´və:ʃən, ´və:rʒən]   n.翻译；说明；译本   (英语四级单词)
• intruder [in´tru:də]   n.闯入者；打扰者   (英语四级单词)
• expedient [ik´spi:diənt]   a.合适的 n.权宜之计   (英语四级单词)