Neutrino physicist wins 2026 Nobel Physics Prize
Neutrino physicist wins 2026 Nobel Physics Prize
中微子物理学家荣获2026年诺贝尔物理学奖
Francis Halzen, a physicist at the University of Wisconsin, Madison, has won the 2026 Nobel Prize in Physics “for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin.” 威斯康星大学麦迪逊分校的物理学家弗朗西斯·哈尔岑（Francis Halzen）荣获2026年诺贝尔物理学奖，获奖理由是“对冰立方中微子天文台（IceCube Neutrino Observatory）的决定性贡献，以及对天体物理起源的高能中微子的发现”。
Halzen spearheaded the development and construction of the IceCube Neutrino Observatory in Antarctica, enabling physicists to capture high-energy neutrinos created in the distant universe. 哈尔岑带头开发并建造了位于南极洲的冰立方中微子天文台，使物理学家能够捕捉到在遥远宇宙中产生的高能中微子。
“It was a great surprise, and I obviously didn’t expect it,” Halzen said during a news conference in Stockholm, Sweden, speaking by phone from Italy. “这真是一个巨大的惊喜，我显然没有预料到，”哈尔岑在瑞典斯德哥尔摩举行的新闻发布会上通过意大利的电话连线说道。
While the Nobel was awarded to Halzen, he emphasized that his work was the result of a “large collaboration” with other researchers. “This reflects on the really courageous people who joined me in this project when really no respectable conservative physicist would have joined me. But many talented people did, and that’s why I’m here,” he said. 虽然诺贝尔奖授予了哈尔岑，但他强调，他的工作是与其他研究人员“大规模合作”的成果。“这反映了那些真正勇敢的人，当没有受人尊敬的保守派物理学家愿意加入我时，他们加入了我的项目。但许多有才华的人做到了，这就是我今天能站在这里的原因，”他说。
“I am shocked and absolutely delighted that Francis was awarded the Nobel this year,” said particle physicist Danielle Norcini of Johns Hopkins University in a statement. “He is the scientific visionary and driving force behind [IceCube]. It has transformed our understanding of the universe by detecting the first high-energy neutrinos from beyond our galaxy, opening an entirely new field of neutrino astronomy. The experiment is the extraordinary achievement of hundreds of scientists, engineers, and collaborators, but Francis was the person who dreamed big enough to imagine an experiment of this scale and then relentlessly pushed to make it a reality.” “弗朗西斯今年获得诺贝尔奖，我感到震惊且无比高兴，”约翰霍普金斯大学的粒子物理学家丹妮尔·诺西尼（Danielle Norcini）在一份声明中表示。“他是[冰立方]背后的科学远见者和驱动力。它通过探测到来自银河系之外的首批高能中微子，改变了我们对宇宙的理解，开辟了一个全新的中微子天文学领域。这项实验是数百名科学家、工程师和合作者共同取得的非凡成就，但弗朗西斯是那个敢于梦想、构想出如此规模实验，并坚持不懈将其变为现实的人。”
Ghost particles
幽灵粒子
As previously reported, neutrinos travel near the speed of light. John Updike’s 1960 poem, “Cosmic Gall,” pays tribute to the two most defining features of neutrinos: They have no charge, and for decades, physicists believed they had no mass (they actually have a teeny bit of mass). 正如之前报道的那样，中微子的运动速度接近光速。约翰·厄普代克（John Updike）1960年的诗作《宇宙胆汁》（Cosmic Gall）向中微子两个最显著的特征致敬：它们不带电荷，且几十年来物理学家一直认为它们没有质量（实际上它们拥有极微小的质量）。
Neutrinos are the most abundant subatomic particle in the universe, but they very rarely interact with any type of matter. We are constantly being bombarded every second by millions of these tiny particles, yet they pass right through us without our even noticing. That’s why Isaac Asimov dubbed them “ghost particles.” 中微子是宇宙中数量最多的亚原子粒子，但它们极少与任何物质发生相互作用。我们每秒钟都在不断受到数百万个这种微小粒子的轰击，但它们却直接穿过我们的身体，甚至让我们毫无察觉。这就是艾萨克·阿西莫夫（Isaac Asimov）称它们为“幽灵粒子”的原因。
That low rate of interaction makes neutrinos extremely difficult to detect, but because they are so light, they can escape unimpeded (and thus largely unchanged) by collisions with other particles of matter. This means they can provide valuable clues to astronomers about distant systems, further augmented by what can be learned with telescopes across the electromagnetic spectrum, as well as gravitational waves. Together, these different sources of information have been dubbed “multimessenger” astronomy. 这种极低的相互作用率使得中微子极难被探测到，但正因为它们非常轻，它们可以在不被其他物质粒子碰撞阻碍的情况下逃逸（因此基本保持不变）。这意味着它们可以为天文学家提供关于遥远系统的宝贵线索，并辅以通过电磁波谱望远镜以及引力波所获得的信息。这些不同的信息来源共同被称为“多信使”天文学。
Neutrinos were first proposed by Wolfgang Pauli in a 1930 letter to colleagues. He was trying to explain some baffling experimental results on radioactive beta decay in atomic nuclei, where energy appeared to be missing—something he deemed (correctly) to be impossible. He thought a new kind of subatomic particle with no charge and no mass may have carried away the missing energy; it was Enrico Fermi who later dubbed it a neutrino. 中微子最初由沃尔夫冈·泡利（Wolfgang Pauli）在1930年写给同事的一封信中提出。他当时试图解释原子核放射性β衰变中一些令人困惑的实验结果，即能量似乎“丢失”了——他认为（正确地）这是不可能的。他认为一种不带电荷且没有质量的新型亚原子粒子可能带走了丢失的能量；后来是恩里科·费米（Enrico Fermi）将其命名为“中微子”。
Clyde Cowan and Frederick Reines first observed these ghostly particles in 1956, thanks to fusion reactions in nuclear power plants that proliferated after World War II. Ten years later, physicists detected the first solar neutrinos. This snagged Ray Davis Jr. and Masatoshi Koshiba a Nobel Prize in 2002, shared with Riccardo Giacconi (who was honored “for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources”). 克莱德·考恩（Clyde Cowan）和弗雷德里克·莱因斯（Frederick Reines）于1956年首次观测到了这些幽灵粒子，这得益于二战后激增的核电站中的聚变反应。十年后，物理学家探测到了首批太阳中微子。这为雷·戴维斯（Ray Davis Jr.）和小柴昌俊（Masatoshi Koshiba）赢得了2002年的诺贝尔奖，并与里卡尔多·贾科尼（Riccardo Giacconi）共享（他因“对天体物理学的开创性贡献，导致了宇宙X射线源的发现”而获奖）。
The only problem was that far fewer solar neutrinos were detected than theory predicted, a conundrum known as the solar neutrino problem. In 1962, physicists discovered a second type (“flavor”) of neutrino, the muon neutrino. This was followed by the discovery of a third flavor, the tau neutrino, in 2000. By then, physicists already suspected that neutrinos might be able to switch from one flavor to another, thanks to 1998 observations by Japan’s Super-Kamiokande collaboration (Super-K). 唯一的问题是，探测到的太阳中微子数量远少于理论预测，这一难题被称为“太阳中微子问题”。1962年，物理学家发现了第二种“味”的中微子——μ中微子。随后在2000年发现了第三种味——τ中微子。到那时，得益于日本超级神冈探测器（Super-K）合作组1998年的观测结果，物理学家已经怀疑中微子可能能够在不同味之间转换。
In 2002, scientists at the Sudbury Neutrino Observatory (or SNO) announced they had solved the solar neutrino problem. The missing solar (electron) neutrinos were just in disguise, having changed into a different flavor on the long journey between the Sun and the Earth. Arthur B. McDonald of SNO and Takaaki Kajita of Super-K shared the 2015 Nobel Prize in Physics for their respective breakthroughs. 2002年，萨德伯里中微子天文台（SNO）的科学家宣布他们解决了太阳中微子问题。那些“丢失”的太阳（电子）中微子只是在伪装，它们在从太阳到地球的漫长旅途中转换成了另一种味。SNO的阿瑟·麦克唐纳（Arthur B. McDonald）和Super-K的梶田隆章（Takaaki Kajita）因各自的突破性贡献共同获得了2015年诺贝尔物理学奖。
An ingenious idea
一个巧妙的构想
The Belgian-born Halzen has been at UW-Madison since shortly after earning his PhD and soon became fascinated by neutrinos. Most neutrino hunters bury their experiments deep underground to help cancel out noisy interference from other sources. Several physicists in the 1980s had proposed water as a good medium for detecting neutrinos from space, while Russian physicists had suggested using radio receivers to capture neutrino signals in Antarctica. Halzen combined the two ideas, reasoning that ice would be an even better medium. He proposed building a neutrino observatory at the South Pole in 1988, since there was already an established research station there. 出生于比利时的哈尔岑在获得博士学位后不久就来到了威斯康星大学麦迪逊分校，并很快对中微子产生了浓厚兴趣。大多数中微子猎人将实验埋在地下深处，以帮助消除来自其他源头的噪声干扰。20世纪80年代，几位物理学家提出用水作为探测太空来源中微子的良好介质，而俄罗斯物理学家则建议在南极洲使用无线电接收器来捕捉中微子信号。哈尔岑将这两个想法结合起来，推断冰会是一种更好的介质。1988年，他提议在南极建立一个中微子天文台，因为那里已经有一个现成的研究站。
Particle physicist Joanne Hewett, of the Yang Institute for Theoretical Physics at Stony Brook, was a postdoc at UW-Madison when Halzen first got the idea. “We went to lunch on a cold winter day at the student union, as usual, and sat next to the window looking out over frozen Lake Mendota,” she recalled. “In the elevator…” 石溪大学杨振宁理论物理研究所的粒子物理学家乔安妮·休伊特（Joanne Hewett）在哈尔岑最初产生这个想法时，还是威斯康星大学麦迪逊分校的一名博士后。“在一个寒冷的冬日，我们像往常一样去学生会吃午饭，坐在窗边看着冰封的门多塔湖，”她回忆道。“在电梯里……”