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arXiv 1105.3976hep-phastro-ph.HE
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来自暗物质衰变的电荷不对称Cosmic Ray信号

Charge Asymmetric Cosmic Ray Signals From Dark Matter Decay

Spencer Chang, Lisa Goodenough

摘要:

在过去的两年里,PAMELA和费米对宇宙射线电子和正电子谱的测量引起了人们极大的兴趣,因为它们与通过暗物质湮灭或衰变产生的20 GeV和1 TeV之间的电子和正电子通量的重要组成部分是一致的。然而,由于测量结果也与天体物理学解释一致,因此信息尚不清楚。本文指出,暗物质在宇宙射线中可以有一个更明显的信号,即电荷不对称性。如果暗物质的丰度是由于遗迹的不对称性,那么这种电荷不对称性就会产生,从而使其衰变产生正电子和电子的不对称性。这类似于重子不对称,衰变中子产生电子而不是正电子。我们探索基准的情况下,暗物质衰变成一个轻子带电希格斯玻色子玻色子或电弱规范玻色子。这些模型在伽马射线和中微子中有可观测到的信号,可以通过费米和冰立方进行测试。最强大的测试将是AMS-02,因为它有能力区分100 GeV以上的电子和正电子电荷。具体地说,有利于正电子的不对称性通常预示着正电子(电子)的正电子比比电荷对称源更大,高能谱更硬(更软)。最后,我们简要讨论了这些情景与主要天体物理学解释的不同之处。

英文摘要:

The PAMELA and Fermi measurements of the cosmic-ray electron and positron spectra have generated much interest over the past two years, because they are consistent with a significant component of the electron and positron fluxes between 20 GeV and 1 TeV being produced through dark matter annihilation or decay. However, since the measurements are also consistent with astrophysical interpretations, the message is unclear. In this paper, we point out that dark matter can have a more distinct signal in cosmic rays, that of a charge asymmetry. Such charge asymmetry can result if the dark matter's abundance is due to a relic asymmetry, allowing its decay to generate an asymmetry in positrons and electrons. This is analogous to the baryon asymmetry, where decaying neutrons produce electrons and not positrons. We explore benchmark scenarios where the dark matter decays into a leptophilic charged Higgs boson or electroweak gauge bosons. These models have observable signals in gamma rays and neutrinos, which can be tested by Fermi and IceCube. The most powerful test will be at AMS-02, given its ability to distinguish electron and positron charge above 100 GeV. Specifically, an asymmetry favoring positrons typically predicts a larger positron ratio and a harder (softer) high energy spectrum for positrons (electrons) than charge symmetric sources. We end with a brief discussion on how such scenarios differ from the leading astrophysical explanations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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