全局样条拟合：从GeV到最高能量的宇宙线能谱与质量组成的统一数据驱动视角
Global Spline Fit: A unified data-driven view of the cosmic-ray spectrum and mass composition from GeV to the highest energies
- Institute of Physics, Academia Sinica（中央研究院物理研究所）
- Fakultät Physik, Technische Universität Dortmund（多特蒙德工业大学物理学院）
- Karlsruhe Institute of Technology（卡尔斯鲁厄理工学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
提出全局样条拟合（GSF）模型，统一描述从GeV到最高能量的宇宙线能谱与质量组成，通过交叉校准能量尺度实现约千个数据点的一致性拟合，并揭示核子通量与常用参数化存在20-50%的偏差。
AI中文摘要：
宇宙线的能谱和质量组成由两类互补的仪器测量：空间和气球搭载的探测器可分辨至亚PeV能量的单个元素，而地面空气簇射观测站将探测范围延伸至$10^{11}$ GeV以上，但只能分辨宽泛的质量组。全局样条拟合（GSF）是一种数据驱动模型，将两者结合为从氢到镍的所有元素通量的单一自洽描述。四个主要质量组的通量由三次基样条参数化，施加平滑性但对谱形不作天体物理预期，同时参与实验的能量尺度偏移在其引用的系统不确定性范围内作为拟合的一部分进行交叉校准。该模型在局部星际谱处定义，并在拟合中考虑了最低能量处太阳调制的影响。拟合使用了最新的高精度数据，包括AMS-02、CALET和DAMPE的元素谱、LHAASO的膝区测量以及皮埃尔·奥格天文台基于荧光的组成测量，描述了约一千个数据点，$\chi^2/\mathrm{ndf}\approx 1.3$，在去除数据集间局部不一致的权重后为0.83，表明一旦能量尺度对齐，全球宇宙线数据整体是一致的。该模型提供通量、质量组成及其完整协方差，以及用于不确定性传播的紧凑降维表示。我们还提供了宇宙线核子通量，其与广泛使用的参数化在四个能量量级上相差20-50%。这超过剩余模型不确定性的数倍，并对大气中微子和缪子通量预测产生直接影响。
英文摘要：
The energy spectrum and mass composition of cosmic rays are measured by two complementary classes of instruments: space- and balloon-borne detectors that resolve individual elements up to sub-PeV energies, and ground-based air-shower observatories that extend the reach to beyond $10^{11}$ GeV but resolve only broad mass groups. The Global Spline Fit (GSF) is a data-driven model that combines both into a single, self-consistent description of the flux of all elements from hydrogen to nickel. The flux of four leading mass groups is parametrized by cubic basis splines, imposing smoothness but no astrophysical expectation on the spectral shape, while the energy-scale offsets of the participating experiments are cross-calibrated within their quoted systematic uncertainties as part of the fit. The model is defined at the local interstellar spectrum, with the effect of solar modulation at the lowest energies accounted for in the fit. The fit uses the most precise recent data, among them the elemental spectra from AMS-02, CALET, and DAMPE, the knee-region measurements of LHAASO, and the fluorescence-based composition of the Pierre Auger Observatory, and describes about one thousand data points with $χ^2/\mathrm{ndf}\approx 1.3$, or 0.83 after de-weighting localized disagreements between data sets, demonstrating that the global body of cosmic-ray data is consistent once energy scales are aligned. The model delivers the flux, the mass composition, and their full covariance, along with a compact reduced representation for uncertainty propagation. We further provide the cosmic-ray nucleon flux, which differs from widely used parametrizations by 20-50% over four decades in energy. This exceeds the remaining model uncertainty several times over and has direct consequences for atmospheric neutrino and muon flux predictions.
