近日，中国科学院高能物理研究所X. Zuo团队研究了“膝盖”区域宇宙射线质子能谱的精确测量。该研究于2025年11月12日发表在《科学通报》杂志上。

研究组基于高海拔宇宙线观测站（LHAASO）的观测数据，实现了宇宙射线质子的高纯度甄别，并完成了0.15-12 PeV能区能谱的精确测量。通过结合大气簇射中电子/光子、缪子与切伦科夫光的联合探测，依托海量事例统计量，使本次能谱测量的统计与系统精度达到可与低能区卫星数据相媲美的水平。

测量显示质子能谱在3 PeV处呈现显著硬化的特征，该特征在达到峰值能量后伴随急剧软化。这种独特的能谱结构与全粒子谱"膝区"高度吻合，表明在PeV能段出现了新的宇宙射线成分——该成分可能与LHAASO近期发现的多个拍电子伏宇宙线加速器（PeVatron）密切相关，为揭示银河系宇宙射线起源提供了关键线索。

附：英文原文

Title: Precise measurements of the cosmic ray proton energy spectrum in the “knee” region

Author: anonymous

Issue&Volume: 2025/11/12

Abstract: We report the high-purity identification of cosmic-ray (CR) protons and a precise measurement of their energy spectrum from 0.15 to 12 PeV using the Large High Altitude Air Shower Observatory (LHAASO). Abundant event statistics, combined with the simultaneous detection of electrons/photons, muons, and Cherenkov light in air showers, enable spectroscopic measurements with statistical and systematic precision comparable to satellite data at lower energies. The proton spectrum shows significant hardening relative to low-energy extrapolations, culminating at 3 PeV, followed by sharp softening. This distinct spectral structure closely aligned with the knee in the all-particle spectrum points to the emergence of a new CR component at PeV energies that might be linked to the dozens of PeVatrons recently discovered by LHAASO, and offers crucial clues to the origin of Galactic cosmic rays.

DOI: 10.1016/j.scib.2025.10.048

Source: https://www.sciencedirect.com/science/article/pii/S2095927325011211