表題番号：2019C-539
日付：2020/04/10
研究課題Investigating Structures in the CALET Electron+Positron Spectrum as Dark Matter or Pulsar Signatures
| 研究者所属（当時） | 資格 | 氏名 | |
|---|---|---|---|
| （代表者） | 理工学術院 国際理工学センター（理工学術院） | 准教授 | モッツ ホルガー マルティン |
| （連携研究者） | WISE | 主任研究員（研究院准教授） | Yoichi Asaoka |
| （連携研究者） | APCTP/Pohang Univ. | JRG Leader | Hiroshi Okada |
| （連携研究者） | KEK / SOKENDAI/ Kavli IPMU, U of Tokyo | 准教授 | Kazunori Kohri |
- 研究成果概要
- The electron+positron spectrum measured by CALET features structures which could be signatures of individual astrophysical point sources, or alternatively Dark Matter (DM) annihilation or decay.
This was investigated using a parametrized model assuming initially a single pulsar as the source of the positron excess fitted to the CALET electron+positron spectrum and the AMS-02 positron-only spectrum. Addition of multiple pulsars, or alternatively the flux from DM annihilating partly through the electron-positron channel can improve the fit significantly by modeling a step-like structure around 350-400 GeV (presented at ICRC 2019 and published in its proceedings). Also presented were updated limits on the DM annihilation/decay rate which are competitive for electron and muon channel, while DM search by gamma-rays favors the tau-channel.
An extension of the Standard Model by U(1)_e-mu gauge symmetry was investigated, finding a DM candidate particle interacting only with electron and muon, with the structure in the CALET spectrum being compatible with its signature (result paper uploaded on arxiv).
Another topic investigated was the anisotropy of the electron-positron flux, calculating an omni-directional limit on dipole anisotropy (presented at ICRC2019 and JPS autumn meeting).