A sublime coincidence slipped by unnoticed last month. While audiences were thrilling to premieres of Tim Burton’s film Alice Through the Looking Glass, in which Alice steps into a strange world where everything is “contrariwise”, physicists in Hungary announced they had possibly found the key to an unseen portion of the universe.

今年5月，一个令人叹为观止的巧合被世人忽视了。就在观众们为蒂姆•波顿(Tim Burton)的电影《爱丽丝梦游仙境2：镜中奇遇记》(Alice Through the Looking Glass)兴奋不已的同时，匈牙利物理学家宣称，他们可能发现了通往宇宙不可见部分的钥匙。在《爱丽丝》一片中，爱丽丝进入了一个奇异的世界，那里的一切东西都是“反的”。

The results, which are a talking point in laboratories the world over, are remarkable because they might point to the existence of a fifth fundamental force. The current model for nature’s physical laws allows for four forces: the electromagnetic force, the strong nuclear interaction, the weak nuclear interaction, and gravitation. A fifth would, literally, be a force for revolutionary change.

匈牙利物理学家的研究结果正成为世界各地实验室的热门话题。这些成果之所以引人注目，是因为它们可能指向第五种基本作用力的存在。自然界物理定律的当前模型允许存在四种作用力：电磁力、强相互作用、弱相互作用和万有引力。毫不夸张地说，第五种基本力会成为一场革命性变革的推动力。

In truth, a revolution is a little overdue. The reason is so-called dark matter, the hidden stuff that makes up more than 80 per cent of the mass of the universe. Astronomers know it is there because of the gravitational effect it exerts on celestial bodies, but it behaves differently from the matter that makes up the visible world.

说实在的，革命来得晚了一些。原因在于所谓的暗物质，这种隐藏的物质占了宇宙质量的80%以上。天文学家知道暗物质的存在，因为它对天体产生了引力效应。不过，暗物质的行为方式与组成可见世界的物质大不相同。

One way of investigating matter is to engineer collisions between particles, and then detect the particles that flutter out of the debris; this is how the elementary

有一种研究物质的方法，是想办法让粒子相互碰撞，然后检测从残骸中飞出的粒子——这正是欧洲粒子物理研究中心(CERN)预言希格斯玻色子这种基本粒子的办法。为此，匈牙利核物理研究所(Institute for Nuclear Physics)的奥蒂洛•克劳斯瑙霍尔考伊(Attila Krasznahorkay)用质子轰击锂同位素，产生了不稳定的铍原子核。这些铍原子核接着就像预期的那样，衰变成了以不同角度飞离彼此的电子-正电子偶。

Higgs boson particle was conjured up at Cern. To this end, Attila Krasznahorkay at Hungary’s Institute for Nuclear Physics, fired protons at lithium isotopes, which produced unstable beryllium nuclei. These beryllium nuclei then decayed, as expected, into electron-positron pairs that flew away from each other at various angles.

然而，不同寻常的是，这些电子-正电子偶似乎喜欢以140度角彼此散开。对此，最简单的解释是这一放射性衰变组合中有一种新的中介粒子。计算似乎表明，这种粒子的质量为17兆电子伏(MeV)，大约是希格斯波色子的七千分之一。

But, anomalously, these electron-positron pairs seemed to have a fondness for shooting away from each other at 140 degrees. The simplest explanation was a new, intermediate particle in the radioactive decay mix. Calculations suggested a mass of 17 megaelectronvolts (MeV), around 7,000 times lighter than the Higgs boson.

尽管科学家曾预言过希格斯波色子的存在，但这种新的活跃粒子没有被预言过。出于这个原因，该团队在公诸于众之前用了三年时间检验自己的结果。正如爱丽丝在被红桃皇后(Red Queen)迷惑时的想法，这完全是一道没有答案的谜题。

While the Higgs was forecast to exist, this new nimble particle was not. That is why the team spent three years checking their results before going public. It is, as Alice muses while being bamboozled by the Red Queen, exactly like a riddle with no answer.

有一种激动人心的可能性是，这种新粒子正是我们熟悉的物质世界与我们看不见的暗物质世界之间缺失的一环。有一种理论认为，新粒子是一种“暗光子”，是一种可能与暗物质有关的尚不为人知的作用力的载体。由加州大学欧文分校(UCI)的冯孝仁(Jonathan Feng)领队开展的重新分析，并不完全支持这种“暗光子”的提议，但确实支持新粒子代表在超短程作用的第五种力的构想。

One exciting possibility is that the new particle is a missing link between our familiar world of matter and the unseen world of dark matter. One theory is that it is a “dark photon”, the carrier of an as yet unidentified force that might be connected with dark matter. A reanalysis led by Jonathan Feng at the University of California, Irvine, does not quite support the “dark photon” suggestion but does back the idea that it represents a fifth force operating over super-short distances.

这一发现也引起了“暗光”(DarkLight)项目实施者的好奇心。他们正在探索包括暗物质和暗能量在内的“黑暗地带”，目前正在寻找10到100兆电子伏之间的暗光子。如今，他们重点关注17兆电子伏，试图揭开相同粒子的面纱。

The finding has also piqued the curiosity of those on the DarkLight project, who are exploring the “dark sector” (both dark matter and dark energy), and are looking for dark photons at between 10 and 100 MeV. They will now target 17 MeV as a priority, in an attempt to unmask the same particle.

如果说这种确认将令人兴奋不已，那就说得太轻了。物理学理论也许十分优美，然而它们并不完善，只能解释可观测宇宙的一小部分。发现一种横跨可见物质世界和不可见暗物质世界的新粒子，会开辟物理学的新天地。

To say that confirmation would be thrilling is an understatement. The theories of physics may be elegant but they are incomplete, capable of explaining only a small fraction of the observable universe. To uncover a new particle that straddles our visible world and the invisible world of dark matter would unlock a new realm of physics.

即便如此，对于我们已知存在于宇宙中的事物，可见物质和暗物质加起来也只能解释不到一半。最大的组成部分据信是暗能量，而暗能量反而可能与暗物质毫无关系。我们了解得越多，真相就越发吊诡。那位自傲于能在早餐前相信六件不可能的事的白皇后，必然会开心地拍起手来。