Nature. 2025 Feb;638(8050):376-382. doi: 10.1038/s41586-024-08543-1. Epub 2025 Feb 12.
The detection of cosmic neutrinos with energies above a teraelectronvolt (TeV) offers a unique exploration into astrophysical phenomena. Electrically neutral and interacting only by means of the weak interaction, neutrinos are not deflected by magnetic fields and are rarely absorbed by interstellar matter: their direction indicates that their cosmic origin might be from the farthest reaches of the Universe. High-energy neutrinos can be produced when ultra-relativistic cosmic-ray protons or nuclei interact with other matter or photons, and their observation could be a signature of these processes. Here we report an exceptionally high-energy event observed by KM3NeT, the deep-sea neutrino telescope in the Mediterranean Sea, which we associate with a cosmic neutrino detection. We detect a muon with an estimated energy of petaelectronvolts (PeV). In light of its enormous energy and near-horizontal direction, the muon most probably originated from the interaction of a neutrino of even higher energy in the vicinity of the detector. The cosmic neutrino energy spectrum measured up to now falls steeply with energy. However, the energy of this event is much larger than that of any neutrino detected so far. This suggests that the neutrino may have originated in a different cosmic accelerator than the lower-energy neutrinos, or this may be the first detection of a cosmogenic neutrino, resulting from the interactions of ultra-high-energy cosmic rays with background photons in the Universe.
探测能量高于1万亿电子伏特（TeV）的宇宙中微子为探索天体物理现象提供了一种独特的方式。中微子呈电中性，仅通过弱相互作用进行相互作用，不会被磁场偏转，也很少被星际物质吸收：它们的方向表明其宇宙起源可能来自宇宙的最远端。当超相对论性宇宙射线质子或原子核与其他物质或光子相互作用时，可以产生高能中微子，对它们的观测可能是这些过程的一个标志。在此，我们报告了由地中海深海中微子望远镜KM3NeT观测到的一个异常高能事件，我们将其与一次宇宙中微子探测联系起来。我们探测到一个估计能量为千万亿电子伏特（PeV）的μ子。鉴于其巨大的能量和近乎水平的方向，这个μ子很可能源自探测器附近一个能量甚至更高的中微子的相互作用。到目前为止测量的宇宙中微子能谱随能量急剧下降。然而，这个事件的能量比迄今为止探测到的任何中微子的能量都要大得多。这表明这个中微子可能起源于与能量较低的中微子不同的宇宙加速器，或者这可能是对一种宇宙成因中微子的首次探测，这种中微子是由超高能宇宙射线与宇宙中的背景光子相互作用产生的。
