| 研究開始時の研究の概要 |
Annihilation or decay of dark matter particle candidates above the mass range of the standard dark-matter candidate, the Weakly Interacting Massive Particle (WIMP), could be revealed through signatures in the TeV-range spectra of electron and positron cosmic rays. Based on the calculation of the expected signatures and comparison with the spectra measured by the CALET and AMS-02 detectors, this project focuses on narrowing down the potential properties of such dark-matter candidates as part of a collective effort to map the huge parameter space opened up by looking beyond the WIMP paradigm.
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| 研究実績の概要 |
Limits on Dark Matter (DM) annihilation and decay from a combined analysis of the latest all-electron spectrum measured by CALET [POS ICRC 2021 (105)] and the positron-only spectrum from AMS-02 [Phys. Rev. Lett. 122, 041102] have been calculated up to 100 TeV DM mass based on the reduction of a purely astrophysical source (SNR, pulsar) background model's fit quality when adding the predicted flux from DM.
This background model was improved in two stages to make the limits more reliable and to include nearby SNR sources as an important background for TeV-range DM.
Starting with a phenomenological broken power-law parametrization of the astrophysical background from distant, with only pulsars calculated as individual extra sources to model the positron excess, as a first improvement, known nearby young SNRs (Vela, Cygnus Loop, Monogem) were also added as individual sources. These intermediate method results were shown at IDM2022 and published in the proceedings.
In the final stage method, the background comprises the overlapping spectra of individual SNR and pulsar sources generated randomly throughout the galaxy, replacing the ad-hoc power law parametrization completely. By studying many samples of this most realistic background description, the background variation is taken into account fully. First results with this method were shown in presentations and a full publication is planned in the near future with the latest published data from CALET.
Furthermore, the underlying cosmic ray propagation model was further improved, with the results also presented at a JPS meeting.
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