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导读
霍金在他的《时间简史》中坦言，当今世界上可能会有些人在有生之年，发现大统一理论。但这个大统一理论并不是爱因斯坦最初想的大统一理论，不可能通过一个简单的美妙的公式来描述和预测宇宙中的每一件事情。因为宇宙是确定性和不确定性相互统一的，量子理论中测不准原理体现了不确定性。
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音乐| 精读 | 翻译 | 词组
No guts, no glory
胸怀万物，行远升高
本文英文部分选自经济学人Science and Technology版块
Particle physics
粒子物理
Fundamental physics is frustrating physicists
物理学家正饱受基础物理学的折磨
No GUTs, no glory
胸怀万物，行远升高
一语双关，一方面文中guts文中主要指Grand unified theories，即大统一理论，主要表达当今粒子物理的困境——看不见大统一理论的前景，也不见粒子物理的”荣光”。另一方面是指虽然粒子物理学陷入困境，但是物理学家依旧在不断寻求真相，正所谓不经历风雨，何以见彩虹。
DEEP in a disused zinc mine in Japan, 50,000 tonnes of purified water held in a vast cylindrical stainless-steel tank are quietly killing theories long cherished by physicists. Since 1996, the photomultiplier-tube detectors (pictured above) at Super-Kamiokande, an experiment under way a kilometre beneath Mount Ikeno, near Hida, have been looking for signs that one of the decillion (1033) or so protons and neutrons within it (of which a water molecule contains ten and eight respectively) has decayed into lighter subatomic particles.
在日本地下深处的一处废弃锌矿里，一只大型不锈钢圆柱体罐中存储着5万吨纯水。这5万吨纯水的存在正在悄然地推翻物理学家之前一直所珍视的物理理论。1996年起，日本岐阜县飞騨市附近神冈矿山地下1000米处，超级神冈探测器里的光电倍增管（如图所示）一直在进行实验，为了在10*33个质子和中子中寻找一种特殊粒子（每一个水分子含10个质子，8个中子），该粒子可以衰变为质量更轻的亚原子粒子。
That those tubes have, in the more than 20 years the experiment has been running, failed to do so is a conundrum for physics, and one that is becoming more urgent with every passing month. Grand unified theories (GUTs), thought since their genesis in the 1970s to be the most promising route to understanding the fundamental forces that bind matter together, predict that protons and neutrons should occasionally disintegrate in a way that breaks what was previously regarded as an iron law of physics—namely that the number of baryons (a class of particle that includes both protons and neutrons) in the universe is constant.
实验已经开展了20多年，但这些光电倍增管并没有找到衰变的粒子，这难倒了物理学家们，而随着时间的流逝，寻找到衰变粒子也变得愈加迫切。大统一理论（GUTs）发轫于20世纪70年代，自提出以来人们一直把该理论看作是理解物质之间的基本力最有前景的理论，并预测质子和中子应该偶尔会分解，这种分解方式打破了之前的物理学铁律，即宇宙间重子数量是守恒地（重子是包括了质子和中子的一类粒子）。
The crucial word, though, is “occasionally”. If the GUT approach is right, the average decay time in question is far longer than the age of the universe itself. But by corralling huge numbers of baryons together, the people behind Super-Kamiokande hoped to spot one decaying much sooner, in just a few years. Those hopes have been dashed. The detector’s most recent estimate, published in January 2017, now pegs the lifetime of a proton at more than 1.6 x 1034 years—and rising. That rules out simpler GUTs (including the first, called SU(5), proposed by Howard Georgi and Sheldon Glashow in 1974). It also encroaches on the predictions of more recent, and more complex, varieties such as “flipped SU(5)”.
但是，这里的关键词是“偶尔”。如果大统一理论正确，上述问题中的质子和中子平均衰变时间远长于宇宙本身年龄。超级神冈探测器的研究人员将大量的重子聚集在一起，希望能够在几年内就能发现一个衰变更快的粒子，但是这些期望都落空了。2017年1月，研究人员发文表示，根据探测器预测，质子寿命为1.6x10*34年或者更长。这和之前较简单的大统一理论不相符（包括第一代大统一理论，即Howard Georgi 和Sheldon Glashow 于20世纪70年代提出的SU(5)理论）。同时，它也影响了最近更为复杂的大统一理论flipped SU(5)的预测可信度。
In the dark
黑暗中摸索
GUTs are among several long-established theories that remain stubbornly unsupported by the big, costly experiments testing them. Supersymmetry, which posits that all known fundamental particles have a heavier supersymmetric partner, called a sparticle, is another creature of the seventies that remains in limbo. ADD, a relative newcomer (it is barely 20 years old), proposes the existence of extra dimensions beyond the familiar four: the three of space and the one of time. These other dimensions, if they exist, remain hidden from those searching for them.
大统一理论是为数几个很长时间以来为人所信服的理论之一，但是却一直没有大型、代价高昂的实验验证支撑的理论。超对称理论指出所有已知基本粒子均有一个质量更高的超对称“伴侣”，叫做“超对称粒子”。超对称理论是19世纪70年代的提出的，至今仍然毫无进展。ADD是该领域的新成员，从发现到现在几乎不到20年。ADD的出现暗示了在我们熟悉的四维空间（空间的三维和时间维度）之外，还存在其他空间，前提是其他维度的空间存在，但目前尚未被人发现。
Finally, theories that touch on the composition of dark matter (of which supersymmetry is one, but not the only one) have also suffered blows in the past few years. The existence of this mysterious stuff, which is thought to make up almost 85% of the matter in the universe, can be inferred from its gravitational effects on the motion of galaxies. Yet no experiment has glimpsed any of the menagerie of hypothetical particles physicists have speculated might compose it.
最后，暗物质构成理论（超对称是其中之一，而不是唯一一个）在过去几年也饱受争议。 这种被认为占宇宙85％的神秘物质的存在性，可以从它对星系运动的引力效应中推断出来。 然而，物理学家对于假想粒子群构成的推测，没有任何实验可以给出模糊的解释。
注：Dark_matter
https://en.wikipedia.org/wiki/Dark_matter
Supersymmetry
https://en.wikipedia.org/wiki/Supersymmetry
Despite the dearth of data, the answers that all these theories offer to some of the most vexing questions in physics are so elegant that they populate postgraduate textbooks. As Peter Woit of Columbia University observes, “Over time, these ideas became institutionalised. People stopped thinking of them as speculative.” That is understandable, for they appear to have great explanatory power. GUTs, for example, seek to merge three of the four known fundamental forces: the strong, weak and electromagnetic interactions (gravity is the fourth). In the process, they explain, among other things, the overwhelming preponderance of matter over antimatter in the universe, a puzzling observation called matter-antimatter asymmetry.
尽管数据缺乏，但所有这些理论为物理学中最令人头痛的问题提供的答案是如此的优雅，以至于它们填补了研究生教科书的空白。 哥伦比亚大学的Peter Woit指出：“随着时间的推移，这些想法变得制度化了。 人们不再认为它们是投机性的。“这是可以理解的，因为它们似乎具有很好的解释力。 例如，GUT（大统一理论）试图合并四个已知的基本力中的三个：强相互作用，弱相互作用和电磁相互作用（重力是第四种）。 在这个过程中，他们解释了一种令人费解的现象，宇宙中反物质占据绝对优势，即物质 - 反物质不对称。
注：GUT
https://en.wikipedia.org/wiki/Grand_Unified_Theory
Antimatter
https://en.wikipedia.org/wiki/Antimatter
The Standard Model, the current best theory in particle physics, cannot do this. GUTs, on the other hand, posit various mechanisms by which subatomic particles (of both matter and antimatter) can fall apart and thus, in some way, allow matter to gain the upper hand. Unfortunately, most of these are untestable with current technology. Recreating the incredibly high energies at which the fundamental forces are thought to merge (those encountered during the early moments of the Big Bang) would require a particle collider larger than the solar system. Of GUTs’ predictions, only the proton and neutron decay being sought by Super-Kamiokande seems testable. And, so far, the tests are negative.
目前粒子物理中最好的理论：标准模型，无法做到这一点。 另一方面，GUTs提出了各种机制，通过这些机制，亚原子粒子（包括物质和反物质）都可以分解，因此，在某种程度上，使物质占上风。 不幸的是，其中大部分是现有技术无法测试的。 物理学家们认为重新创造可用于合成基本力的巨大能量需要比太阳系更大的粒子对撞机。在GUTs的预言中，只有超级神冈探测器（Super-Kamiokande）寻求的质子和中子衰变似乎是可以测试的。 而且，到目前为止，测试结果都是负面的。
注：Standard Model
https://en.wikipedia.org/wiki/Standard_Model
Subatomic particle
https://simple.wikipedia.org/wiki/Subatomic_particle
Super-Kamiokande
https://en.wikipedia.org/wiki/Super-Kamiokande
A similar story can be told for supersymmetry. This theory can, among other things, account for the value of the mass of the Higgs boson (a recently discovered particle that is responsible for imbuing other particles with mass) in a way that the Standard Model cannot. Nothing in that model gives a precise value for the Higgs’s own mass, and calculations from first principles, based on quantum theory, suggest it should be enormous—roughly a hundred million billion times higher than its measured value. Physicists have therefore introduced an ugly fudge factor into their equations (a process called “fine-tuning”) to sidestep the problem. Supersymmetry resolves it more neatly.
超对称理论 （supersymmetry）可以来说明这些现象。超对称理论能解释标准模型（Standard Model）无法解释的事情，比如说希格斯玻色子 （Higgs boson） 的质量值和其他事情问题。（希格斯玻色子是近期发现的粒子，它的存在使其他粒子含有质量）。标准模型不能计算出希格斯玻色子自身的明确质量值。在量子理论的基础上，根据第一性原理的计算方法，希格斯玻色子的质量是巨大的 - 大概高于其估值的10*1018倍。物理学家因此把一个完全捏造的因数运算到他们的方程中，（这个过程叫做 “微调”），以此来回避此问题。超对称能更巧妙的解决这个问题。
The problem arises because as a Higgs boson moves through space, it encounters “virtual” versions of Standard Model particles (like photons and electrons) that are constantly popping in and out of existence. According to the Standard Model, these interactions drive the mass of the Higgs up to improbable values. In supersymmetry, however, they are cancelled out by interactions with their sparticle equivalents.
问题的产生原因是：当希格斯玻色子在宇宙中穿行，它遇见了“不稳定”的若有若无的标准模型粒子（比如光子和电子）。根据标准模型理论（Standard Model），这些粒子相互作用使得希格斯玻色子达到难以置信的质量值。然而，根据超对称理论，在和超对称粒子相等物相互作用下,希格斯玻色子的质量会相互抵消。
Various flavours of supersymmetry predict that one or other of the sparticles should have popped up by now in the Large Hadron Collider. The LHC (one of the detectors of which is pictured above, under construction) is the principal machine at CERN, the world’s biggest particle-physics laboratory, near Geneva. But of sparticles it has seen no sign.
各种超对称理论的“味”预计，在大型强子对撞机中希格斯玻色子的超对称粒子或其它超对称粒子应该已经出现。大型强子对撞机（如上图所示：其中之一的探测器正在建造中）是欧洲核子研究组织（CERN）中最重要的机器设备。该组织位于日内瓦附近，是世界上最大的粒子物理学实验室。但其并没有发现超对称粒子。
The mass of the Higgs is one aspect of what is known as the hierarchy problem in physics. This is the riddle of why gravity is so much weaker than the other three fundamental interactions—as demonstrated by the fact that a fridge magnet can pick up a paper clip, and in so doing easily overcome the gravitational force of a whole planet. The connection with the Higgs-mass problem is that if the Higgs really was huge, that would also make other particles (protons, neutrons and so on) more massive, thus giving them much stronger gravitational fields. Whereas supersymmetry resolves the problem via sparticles, theories with extra dimensions (such as ADD) do so by allowing gravity, but not the other three fundamental forces, to spread through these dimensions. That dissipates gravity’s strength in comparison with that of the other three.
在物理界，希格斯玻色子的质量是等级问题（hierarchy problem）的一个方面。这是重力要比其他三个基本相互作用力微弱很多的原因 —— 事实证明一个冰箱贴可以吸起一个回形针，并且轻而易举的克服了地球的引力。这个事实和希格斯玻色子质量问题的联系在于，如果希格斯玻色子真的是巨大的，那其他粒子（质子，中子等）也会变大，从而也给予其他粒子更强的引力场。然而，超对称通过超对称粒子阻止了这种情况的发生。有些理论用额外维度（如ADD）来解决这个问题是通过重力，（而不是三个基本力）扩散到其他维度的说法，这也是为什么在与其他三个基本力相比之下，重力的强度消散了。
This happens because gravitons (the hypothetical particles that carry the gravitational force) leak into those dimensions. If gravitons were created in the LHC, which some theories suggest is possible, then signs of such leakage could be sought. So far, though, no LHC-generated gravitons have turned up.
这是因为引力子(携带引力的假想粒子)泄漏到这些维度中。一些理论认为在大型强子对撞机中产生引力子是可能的，那么物理学家就可以寻找这种泄漏的迹象。但到目前为止，还没有出现大型强子对撞机生成的引力子。
The dark-matter picture is more complex still. There are plenty of lines of evidence indicating the stuff exists, and many theories that propose this or that particle to explain what it might actually be. As its name suggests, dark matter is difficult to spot. Though it participates in gravitational interactions, it does not interact electromagnetically. This means it neither emits nor absorbs light. Nor does it get involved with the strong force—the one that holds atomic nuclei together. One class of hypothetical objects that might be dark matter do interact via the weak force, a phenomenon that also controls some sorts of radioactive decay. These objects are called WIMPS (weakly interacting massive particles). Exactly what they are remains obscure. Some sparticles would fit the bill, but there are other candidates. Several possible WIMPs, though, should be detectable by experiments that, like Super-Kamiokande, involve large tanks of liquid.
暗物质图像更复杂。有大量的证据表明这些物质存在，还有许多理论提出这个或那个粒子来解释它到底是什么。顾名思义，暗物质是很难发现的。虽然它参与了引力的相互作用，但它并没有电磁作用。这意味着它既不发光也不吸收光。它也不参与强力—一种把原子核结合在一起的力-。 一类可能是暗物质的假想物体通过弱力相互作用，这种现象也控制着某种放射性衰变。 这些对象被称为WIMPS（弱相互作用大质量粒子）。确切地说，它们仍然是模糊的。有些粒子是符合要求的，但他们也是候选对象。不过，有几个可能的WIMPs（弱相互作用大质量粒子）应该可以利用像超级神冈探测器一样的实验设备检测出来，但需要用到大量液体。
Tank warfare
容器战
In those experiments the preferred fluid is not water but liquid xenon, and the phenomenon being sought is not a spontaneous decay but an interaction between a WIMP and an atomic nucleus, which will generate a flash of light that can be detected by arrays of photomultiplier tubes at the top and bottom of the tank. Xenon is the darling of dark-matter hunters because it is a heavy element with a large nucleus. It is thus more likely to get hit than lighter atoms. It is also reasonably cheap, unreactive and easy to purify. So far, however, the xenon-filled vats have remained as dark as the matter they hope to find. Two of the world’s three most sensitive xenon-tank experiments reported their latest results in October 2017. Searches by XENON1T, under Gran Sasso, a mountain in Italy, and PandaX-II at China Jinping Underground Laboratory, in Sichuan, which contain 3,500kg and 500kg of xenon respectively, came up empty-handed. The third of the trio, 368kg of xenon in an experiment called LUX, in a former gold mine in the Black Hills of South Dakota, also failed to find WIMPs before it was shut down in May 2016.
在这些实验中首选的液体不是水而是液态氙,物理学家所寻求的现象不是一个自发衰变，而是一个弱相互作用的大质量粒子和一个原子核之间的相互作用,这个作用将在管箱的顶部和底部产生一个能被阵列光电倍增器探测到的闪光。氙是那些寻找暗物质的物理学家的最爱，因为它是拥有大核子的重元素。因此，它比更轻的原子更容易被击中。它也相当便宜、不参与反应、易于提纯。然而，到目前为止，这些充满氙气的容器实验结果仍然像他们希望找到的物质那样黑暗。世界上三个最敏感的氙容器实验中，有两个在2017年10月报告了最新的结果。他们是位于意大利格兰萨索(Gran Sasso)山下的XENON1T实验室和位于中国四川金平的地下的PandaX-II实验室，两者分别有3500千克和500千克的氙，他们的搜索最后都是空手而归。第三个实验室LUX位于南达科他州布莱克山区旧金矿矿洞中，该实验室有368千克的氙，在2016年5月被关闭之前，这个实验室也没能找到WIMPs。
阵列光电倍增器：基于光电倍增管和光电二极管阵列两种接收方式的荧光光谱仪
These WIMP searches have become progressively larger over the past two decades. XENON1T, for instance, was preceded by two detectors, XENON10 (15kg) and XENON100 (165kg), the first of which started work in 2006. LUX will be followed by LUX-ZEPLIN, which will use 7,000kg of the stuff. In China, PandaX-4T (4,000kg) is already being built and there are tentative plans for a whopping 30,000kg detector (PandaX-30T). Even something of that size, though, would not altogether rule out WIMP-based hypotheses were it to find no evidence of WIMPS. The nature of the models means that they can be tweaked almost endlessly.
这些WIMP搜索的设备规格在过去20年里变得越来越大。例如，XENON1T之前有两个检测器，XENON10 (15kg)和XENON100 (165kg)，第一个在2006年开始工作。LUX由LUX-ZEPLIN替代，将使用7000kg的产品。在中国，PandaX-4T (4000kg)已经在建造中，并且有一个巨大的30,000kg探测器的初步计划(PandaX-30T)。然而，由于它没有发现wimp的证据，即使是这样的规模，也不能完全排除基于wimp的假设。这些模型的本质意味着它们几乎可以无休止地调整。
The history of the search for proton decay, meanwhile, goes back even further. The first experiment to be built to look for it in the mine that now hosts Super-Kamiokande was called KamiokaNDE, and used a piddling 3,000 tonnes of water for the purposes of detection. That was in 1983. Hyper-Kamiokande, Super-Kamiokande’s successor, should be ready to go in 2026. It will survey an astonishing 500,000 tonnes of water (ten times that of its predecessor) for 20 years or more, pushing the minimum average lifetime of a proton up to 1035 years if it fails to find one.
同时，质子衰变的研究历史更为悠久。第一项用于探测质子衰变的实验是1983年在矿井中，使用超级神冈探测器开展的实验，又称神冈无损检测，该实验对3000吨水进行探测。超级神冈探测器的下一代---顶级神冈探测器将于2026年启用，届时将对50万吨水（是超级神冈的10倍）进行至少为期20年的探测。如果没能找到衰变的质子，质子的最低平均生命周期将提高到1035年。
Persistence in the face of adversity is a virtue, of course. And, as all this effort shows, physicists have been nothing if not persistent. Yet it is an uncomfortable fact that the relentless pursuit of ever bigger and better experiments in their field is driven as much by belief as by evidence.
面对困难，坚韧不拔是种美德。所有这些努力都表明，如果没有坚持不懈的品质，物理学家难以取得成就。但是令人颇感难受的是，物理学家在其研究领域内，不断地追求更大规模、更高级的试验，背后的驱动力，一半是信念，另一半才是科学证据。
The core of this belief is that Nature’s rules should be mathematically elegant. So far, they have been, so it is not a belief without foundation. But the conviction that the truth must be mathematically elegant can easily lead to a false obverse: that what is mathematically elegant must be true. Hence the unwillingness to give up on GUTs and supersymmetry. New theories have been made by weaving together aspects of older ones. Flipped SU(5), for example, combines GUT with supersymmetry to explain the Higgs mass, the hierarchy problem and matter-antimatter asymmetry—and provides dark-matter candidates to boot. With every fudge applied, though, what were once elegant theories get less so. Some researchers are therefore becoming open to the possibility that the truth-is-beauty argument is a trap, and that the universe is, in fact, fundamentally messy.
这种信念的核心是认为自然界的法则在数学上精妙绝伦。鉴于长期以来一直如此，这种想法也并非无本之木。但是这种对于精妙数学的信念很容易走入另一个误区，即认为一切数学上精妙的东西都是真实的。因此，他们不愿因放弃大统一理论以及超对称理论。现在这些新的理论其实是把旧理论相关的部分串联起来。比如：Flipped SU(5)结合了大统一理论和超对称理论，来解释Higgs 粒子、级列问题以及物质-非物质不对称，并且提供暗物质候选对象。然而每次出现问题都使得原先精妙的理论逐渐失色。所以，有些研究人员变得更加开明，他们开始面对一种可能性：自然之美的论调是个陷阱，事实上宇宙本身杂乱不堪。
To boot：加之，而且；此外，除此以外，额外地
The beauty myth
美丽的神话
.One such is Sabine Hossenfelder of the Frankfurt Institute for Advanced Studies, in Germany. She argues that the appeal of GUTs, supersymmetry and the like rests on their ability to explain “numerological coincidences” that do not need to be explained. Perhaps, to take one example, the universe simply started out with more matter than antimatter in it, rather than this being a consequence of its subsequent evolution. As she points out, no theory precludes this possibility—it is just that it is not very elegant. Similarly, she says, “It’s not like anybody actually needs supersymmetry to explain anything. It’s an idea widely praised for its aesthetic appeal. Well, that’s nice, but it’s not science.”
德国法兰克福高级研究院的萨比娜·豪森菲尔德就是其中之一。他认为，大统一理论、超对称理论和其他一些类似理论的魅力在于能够解释“数学巧合”，而事实上这些巧合不必解释。例如，可能宇宙起源之时物质就要比非物质多，而不是经过演化之后物质才多于非物质。她表示，没有理论可以排除这种可能性—只不过这样看起来毫无科学之美。同样的，她还认为：“可能不是所有人真的都需要超对称理论来解释什么现象。这是一个美学角度得到广泛赞誉的理念。尽管看起来很美，但它不是科学。”
Dr Hossenfelder’s remains a minority opinion, but other heterodox approaches, perhaps because they offer the possibility of experimental testing, are also gaining ground. Surjeet Rajendran of the University of California, Berkeley, for example, is using a “suck it and see” method that would have been familiar to 19th-century physicists, who did not yet have a huge body of theory to guide and constrain their experiments. He is searching for dark-matter particles outside the range of masses that conventional theories of what WIMPs are predict.
豪森菲尔德博士代表的是少数人的观点，但是其他异见者更认可这种观点（美学角度的理论），或许他们提供了一些实验验证的可能性，而且也正在取得进展。比如加州大学伯克利分校的Surjeet Rajendran，他采用了十九世纪的物理学家来都很熟悉的“试了才知道”的方法，，那时他们并没有很多理论指导和约束他们的实验。Surjeet Rajendran正在找寻在大质量弱相互作用粒子理论预测之外的暗物质粒子。
suck it and see 试了才知道
That he and his colleagues are able to do so is, in part, because their apparatus is small and cheap—and thus worth a punt by a grant committee. At its core lies a sensitive magnetometer, known as a SQUID. This should pick up the tiny magnetic fields that dark-matter particles would be expected to generate indirectly by weak-force interactions with atomic nuclei as they fly through the apparatus. As Dr Rajendran’s experiments are carefully shielded, only such particles, with their extraordinarily weak interactions with normal matter, would be expected to enter the apparatus and be detected.
他和他同事之所以能够开展这项任务，是因为他们的仪器小而便宜——因此拨款委员会认为值得投资。仪器的中心是一个灵敏的磁力计，被称为超量子干涉作用装置SQUID。当原子核通过这个仪器的时候，由于暗物质和原子核的弱相互作用，其会间接地产生微弱的磁场，而这种装置可以感知它。正如Rajendran博士的实验所竭力捍卫的，只有粒子们同普通物质产生的超凡的弱作用才会预计进入仪器并被检测出。
Other teams, working within the limits of conventional-but-as-yet-unproven theory, have similarly economical, collider-eschewing ideas. ADD and other, related, ideas predict that extra dimensions are populated by non-Standard Model particles. Tiny objects, held less than a tenth of a millimetre apart, should experience forces transmitted by these particles in ways detectable by bench-top apparatus. Such forces would, for instance, cause the gravitational attraction between the objects in question to deviate from Newton’s inverse-square law, which states that the gravitational force between two bodies is inversely proportional to the square of the distance between them.
在常规的但尚未被证实的理论范围内，其他一些团队也有类似的经济型碰撞机想法。 ADD和其他相关想法预测，其他的维度将会由非标准型模型粒子构成的。一些相隔不到0.1mm的微小物质在受到其他粒子的作用力后应该能被台式仪器检测出来。例如，这些作用力会引起物体间的引力，从而偏离牛顿的万有引力定律，即两个物体之间的万有引力与两个物体之间的距离的平方成反比。
AndrewGeraci and his team at the University of Nevada, in Reno, hope to find such deviations by tracking the movement of a glass bead just 300 billionths of a metre across, cradled in a network of laser light. Similarly, Eric Adelberger of the University of Washington, in Seattle, is employing a torsion balance, a piece of kit invented over 200 years ago for the purpose of measuring weak forces (Henry Cavendish, a British natural philosopher of the 18th century, used one, illustrated below, to work out the density, and therefore the mass, of Earth). A number of other groups are searching for the effects of these forces within molecules that consist of just two atoms. Any extradimensional forces experienced by the atoms will translate into minute differences between the energy levels of their electrons. Such differences can, in turn, be probed spectroscopically by using a laser to excite the electrons and measuring the wavelengths at which they then emit light.
AndrewGeraci 和他在雷诺市内华达大学的研究团队期望追踪到从激光网中诞生的一个直径三百亿分之一米的玻璃珠动作的偏差。在西雅图华盛顿大学的Eric Adelberger正在使用扭秤，这是一件两百年前被发明用作测量弱作用力的装置（一个英国18世纪的自然哲学家Henry Cavendish用它去测量地球的密度和重量）。许多组织正在寻找两个原子组成的分子中的力的作用。当异次元的力作用于任何原子，这种力将会显示为他们电子能量级的细微差异。通过使用激光来激发电子，光谱设备能显示出这些差异，并且能测量出他们发射出的光的波长。
minute differences 细微差异
Advances in laser physics of this sort are also behind ACME, an experiment occupying about 100 square metres of laboratory space at Harvard University. ACME is looking for the sparticles of supersymmetry. But it is doing so indirectly, by monitoring their putative effects on the properties of single electrons with incredible accuracy. The electrons being looked at are inside molecules of thorium monoxide, which has some unique properties that make it suited to the search.
这类激光物理学的进展也落后于ACME，这项实验在哈佛大学大约100平米的实验室里进行。ACME正在寻找超对称(性)粒子，但是也只能间接论证高精度监测对单个电子性能的推论影响。被监测的电子在一氧化钍的分子里面，它的有些性能很独特，正好适合这一研究。
According to the Standard Model, an electron’s charge is spherically distributed. Interactions with sparticles, however, would deform this sphere in a way that would create a slight positive charge in one place and an equal, negative charge opposite it. When placed in an electric field, this deformed electron would experience a force called a torque that would cause it to rotate. The stronger the field, the more torque there would be. There is a particular electron in a molecule of thorium monoxide that is exposed, by its location between the thorium and oxygen atoms, to an electric field of 100 gigavolts per centimetre—a million times greater than anything that can be produced in a laboratory. That would magnify the torque on a distorted electron to the point where it should be detectable with lasers.
根据标准模型（the standard model）,电子的电荷以球体的形式分布。但是，如果和超对称粒子交互，球体将会变形，会在某一处产生一个微小的正电荷，并在相对的位置产生一个相等的负电荷。如果这一变形的电子放在电场内，它会受到扭力的作用而旋转。电场越强，扭力越大。一氧化钍分子里存在着一种特殊的电子，它位于在钍原子和氧原子之间，如果放在100吉电子伏特/厘米的电场内-这比能在实验室里能产生的任何东西都大100万倍，变形的电子受到的扭力会放大到能被激光器检测到。
In 2014 the group behind ACME published work showing that the electrons they were looking at had properties in line with those predicted by the Standard Model. At the sensitivities they were able to achieve, that ruled out interactions with the sorts of sparticles that might have been created at the LHC. ACME has been souped up since. David DeMille of Yale University, one of the physicists behind the project, says the collaboration will be publishing its next round of measurements within months, pushing into territory the LHC is not powerful enough to explore.
2014年ACME团队发布的报告表明，他们正在观察的电子的性质和标准模型理论预测的一致。在他们当时能达到的灵敏度内，排除了与在大型强子对撞机（LHC）产生的超对称粒子交互的可能性。因此ACME进行了升级。项目成员之一的耶鲁大学物理学家David DeMille说，合作团队将在近几个月内发布下一轮的测量结果，扩展到大型强子对撞机（ LHC）没有能力探索的领域。
So far, though, the small-is-beautiful approach has been no more successful than the big colliders in coming up with new phenomena. Most physicists therefore want to double down, construct an even bigger collider and hope something interesting emerges from that. Whether politicians and taxpayers will be up for this remains to be seen. That fundamental physics has got as far as it has is, essentially, a legacy of its delivery to political leaders of the mid-20th century of the atom and hydrogen bombs. The consequence of this was that physicists were able to ask for expensive toys—for who knew what else they might come up with. That legacy has now been spent, though, and any privilege physics once had has evaporated. This risks leaving in permanent limbo not only the GUTs and their brethren, but also the sceptical idea of DrHossenfelder that the Standard Model really is all there is. And that would surely be the most depressing result of all.
然而到目前为止，“因小而美”的研究方法在处理新现象方面还是比不上大对撞机。因此大多数科学家想要另外建一个更大的对撞机，希望能有些新发现。政治家和纳税人是否会同意这方案还有待观察。基础物理基本上已经走到尽头，它留给政治领导人的遗产是20年代中叶的原子弹和氢弹。其结果是物理学家有能力寻求昂贵的玩具-谁知道他们还能再想出什么玩意儿来。然而，遗产已经花光，物理学家曾经有的任何特权也消失殆尽了。现在不仅大统一理论以及相关理论陷入困境，而且Hossenfelder博士怀疑标准模型是否真的能解释一切。这肯定是最令人沮丧的结果了。
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