Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), E-28040 Madrid, Spain.
I. Physics Institute and JARA-FAME, RWTH Aachen University, D-52056 Aachen, Germany.
Phys Rev Lett. 2019 Feb 1;122(4):041102. doi: 10.1103/PhysRevLett.122.041102.
Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million positrons collected by the Alpha Magnetic Spectrometer on the International Space Station. The positron flux exhibits complex energy dependence. Its distinctive properties are (a) a significant excess starting from 25.2±1.8 GeV compared to the lower-energy, power-law trend, (b) a sharp dropoff above 284_{-64}^{+91} GeV, (c) in the entire energy range the positron flux is well described by the sum of a term associated with the positrons produced in the collision of cosmic rays, which dominates at low energies, and a new source term of positrons, which dominates at high energies, and (d) a finite energy cutoff of the source term of E_{s}=810_{-180}^{+310} GeV is established with a significance of more than 4σ. These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter annihilation or from other astrophysical sources.
基于国际空间站阿尔法磁谱仪收集的 190 万正电子，我们对宇宙射线正电子进行了高达 1 TeV 的精确测量。正电子流表现出复杂的能量依赖性。其独特的性质包括：（a）与较低能区的幂律趋势相比，从 25.2±1.8 GeV 开始有显著的过剩；（b）在 284_{-64}^{+91} GeV 以上急剧下降；（c）在整个能量范围内，正电子流很好地由与宇宙射线碰撞产生的正电子相关的项和在高能区占主导地位的新的正电子源项的和来描述；（d）源项的能量截止值 E_{s}=810_{-180}^{+310} GeV 被确定，其置信度超过 4σ。这些关于宇宙射线正电子的实验数据表明，在高能区，它们主要来源于暗物质的湮灭或其他天体物理源。
