Origin of the positron excess in cosmic rays.
Origin of the positron excess in cosmic rays.
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DOI：
10.1103/physrevlett.103.051104
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发表时间：
2009-03
影响因子：
8.6
通讯作者：
P. Blasi
中科院分区：
文献类型：
--
作者：
P. Blasi
我们发现，帕梅拉实验在10GeV和100GeV之间测量到的正电子过剩很可能是银河系宇宙线起源标准假设的自然结果。“过剩”的产生是因为正电子在源内部作为强子相互作用的二次产物产生，但导致正电子通量自然解释的关键物理因素是，二次生产发生在宇宙射线加速的同一区域。因此，次级正电子(和电子)参与了加速过程，并具有非常平坦的光谱，这是在银河系中传播后观察到的正电子过剩的原因。这种影响是不可避免的，尽管其强度取决于超新星遗迹演化后期的环境参数值。
We show that the positron excess measured by the PAMELA experiment in the region between 10 and 100 GeV may well be a natural consequence of the standard scenario for the origin of Galactic cosmic rays. The "excess" arises because of positrons created as secondary products of hadronic interactions inside the sources, but the crucial physical ingredient which leads to a natural explanation of the positron flux is the fact that the secondary production takes place in the same region where cosmic rays are being accelerated. Therefore secondary positrons (and electrons) participate in the acceleration process and turn out to have a very flat spectrum, which is responsible, after propagation in the Galaxy, for the observed positron excess. This effect cannot be avoided though its strength depends on the values of the environmental parameters during the late stages of evolution of supernova remnants.