The proton's inner life is a complex affair. The three "valence" quarks that make up its charge live in a seething sea of shorter-lived quarks that pop into and out of existence from the quantum vacuum.

质子内部是一个复杂的世界。三个给出质子电荷的"价"夸克生活在一个沸腾的海洋中，旁边充斥着在量子真空中产生而又消失的寿命极端的夸克。

Pulling the strings is a melange of particles called gluons. Quarks carry both electricalcharge and a property known as colour charge. Just as photons are exchanged between particles with electric charge to produce the electromagnetic force, gluons are exchanged between colour-charged quarks. This exchange produces the strong nuclear force that binds them together.

把它们束缚在一起的拉弦的则是一类称为胶子的粒子。夸克携带电荷和另一种称为色荷的属性。正如带电粒子交换光子产生了电磁力一样，胶子在带色的夸克之间交换。这种交换产生强大的核力，把它们结合在一起。

Except there is a difference. Photons are electrically neutral, but gluons themselves carry colour charge, and so feel their own force. That raises an interesting question: can we forget the quarks altogether, and make matter just of gluons stuck to each other?

但是还是有差别的。光子是电中性的，但胶子本身也带有色荷，所以它们有自己的相互作用力。这就产生了一个有趣的问题：能不能完全不要夸克，使物质仅仅只是相互粘接的胶子？

The possibility of "glueballs" has tantalised physicists for three decades. In 1994, CERN's Crystal Barrel experiment provided the first of a series of putative sightings. Yet two decades on, says particle theorist Frank Close, we are no closer to saying what truth there was in the claims. Any number of electrically neutral, strongly-interacting particles will in all practically conceivable situations mix with glueballs and muddy the waters. "There is nothing that goes against the idea of glueballs existing," says Close. "But how to prove it is still bugging me."

"胶球"的可能性已经引诱了物理学家三十年。 1994年，欧洲核子研究中心的水晶桶实验提供了一系列中的第一个候选发现。然而二十年来，粒子理论家的Close说，我们并没有更接近说什么是正确的。任意数量的电中性的强相互作用粒子，在几乎可以想象的任何实际情况下，和胶球的信号混杂而会把水搅浑。 "没有什么违背现有的胶球理论"，CLose说，"但是如何证明它仍困扰着我。"

• complex [´kɔmpleks]   a.复杂的 n.综合企业   (初中英语单词)
• charge [tʃɑ:dʒ]   v.收费；冲锋 n.费用   (初中英语单词)
• existence [ig´zistəns]   n.存在；生存；生活   (初中英语单词)
• altogether [,ɔ:ltə´geðə]   ad.完全；总而言之   (初中英语单词)
• possibility [,pɔsə´biliti]   n.可能(性)；希望；前途   (初中英语单词)
• crystal [´kristəl]   n.水晶 a.水晶的   (初中英语单词)
• barrel [´bærəl]   n.(琵琶)桶；圆筒   (初中英语单词)
• series [´siəri:z]   n.连续；系列；丛书   (初中英语单词)
• electrical [i´lektrikəl]   a.用电的；与电有关的   (高中英语单词)
• neutral [´nju:trəl]   a.中立(国)的   (高中英语单词)
• particle [´pɑ:tikl]   n.微粒；极小量   (高中英语单词)
• saying [´seiŋ, ´sei-iŋ]   n.言语；言论；格言   (高中英语单词)
• conceivable [kən´si:vəbəl]   a.可想象得出的   (英语四级单词)