Study of Indirect Detection of Dark Matter by Cosmic-Ray Electron and Positron Observations

粒子物理学指出，在WIMP暗物质的湮灭过程中，可以产生单能电子和正电子，如最轻的稳定超对称粒子的中性子和宇宙超维模型的Kaluza-Kein粒子。在这项研究中，我考虑了通过探测这些电子来间接观测暗物质的可能性。100GeV以上的电子和正电子的能谱和到达方向对于探测WIMP湮没中的电子-正电子对是至关重要的。然而，对能谱的观测很少，对到达方向的观测也没有。由于我们在南极用PPB-BET观测到了100GeV到1TeV的宇宙线电子，通过对PPB-BET数据集的分析，我推导出了~100GeV到~1TeV能量范围内电子的能谱和到达方向。尽管观测到的电子光谱在亚TeV区域可能有一个驼峰，但电子和正电子观测的统计量不足以讨论WIMP暗物质贡献的细节。为了大大增加统计的数量，需要通过空间利用，如国际空间站上的CALET，对高能电子和正电子进行更长时间的曝光观测。因此，我模拟了用CALET观测到的WIMP暗物质湮灭过程中电子和伽马射线的能谱。模拟结果表明，对电子的高精度测量使我们能够探测到银晕中WIMP暗物质湮灭的独特特征。

It has been pointed out in particle physics that mono-energetic electrons and positrons can be produced in the annihilation of WIMP dark matter such as neutralino of the lightest stable supersymmetric particle and Kaluza-Kein particle of universal extra dimension models. In this study, I considered the possibility of the indirect observations of dark matter by the detection of these electrons. The energy spectrum and arrival directions of electrons and positrons in the energy range above 100GeV is crucial to detect electron-positron pairs from WIMP annihilations. However, there are few observations for the energy spectrum and no observations for the arrival directions. Since we have observed cosmic-ray electrons from 100GeV to 1TeV with PPB-BETS in Antarctica, from the analysis of the data sets of PPB-BETS, I derived the energy spectrum and arrival directions of electrons in the energy range of 〜100GeV to 〜1TeV. Although the observed electron spectra might have a hump in the region of sub-TeV, the amount of statistics of the electron and positron observations are insufficient to discuss the details of the contribution of WIMP dark matter. In order to increase the greatly the amount of statistics, it is required to observe the high-energy electrons and positrons for much longer exposure times by space utilization such as CALET on the ISS. Hence, I simulated the energy spectrum of electrons and gamma rays from WIMP dark matter annihilations observed with CALET. The simulated results suggest that a high precise measurement of the electrons enable us to detect distinctive features from WIMP dark matter annihilations in the Galactic halo.