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凑巧被世人忽略了。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,匈牙利物理学家声称,他们有可能找到了通向宇宙不可见部分的钥匙。在《爱丽丝》一片中,爱丽丝转入了一个无法解释的世界,那里的一切东西都是“鼓吹的”。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于是以沦为世界各地实验室的热门话题。

这些成果之所以引人注目,是因为它们有可能指向第五种基本作用力的不存在。自然界物理定律的当前模型容许不存在四种作用力:电磁力、强劲相互作用、很弱相互作用和万有引力。从不滑稽地说道,第五种基本力会沦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.说道觉得的,革命远比晚了一些。


不过,暗物质的不道德方式与构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,是想要办法让粒子互相撞击,然后检测从残骸中飞向的粒子——这正是欧洲粒子物理研究中心(CERN)应验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)用质子炮击锂同位素,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,裂变出了以有所不同角度飞离彼此的电子-正电子极。

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-正电子极或许讨厌以140度角彼此前行。回应,最简单的说明是这一放射性裂变人组中有一种新的中介粒子。

计算出来或许指出,这种粒子的质量为17兆电子叱(MeV),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.尽管科学家曾应验过希格斯波色子的不存在,但这种新的活跃粒子没被应验过。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)欺骗时的点子,这几乎是一道没答案的谜题。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,这种新的粒子正是我们熟知的物质世界与我们看不到的暗物质世界之间缺陷的一环。

有一种理论指出,新的粒子是一种“亮光子”,是一种有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)领队积极开展的新的分析,并不几乎反对这种“亮光子”的建议,但显然反对新的粒子代表在超强短程起到的第五种力的设想。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.这一找到也引发了“暗光”(DarkLight)项目实施者的好奇心。

他们正在探寻还包括暗物质和亮能量在内的“黑暗地带”,目前正在找寻10到100兆电子叱之间的暗光子。如今,他们重点注目17兆电子叱,企图揭露完全相同粒子的面纱。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.如果说这种证实将令人兴奋不已,那就说道得太重了。物理学理论或许十分典雅,然而它们并不完备,不能说明可观测宇宙的一小部分。


找到一种跨越可见物质世界和不可见暗物质世界的新粒子,不会修筑物理学的新天地。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,对于我们未知不存在于宇宙中的事物,可见物质和暗物质特一起也不能说明将近一半。