Indirect Detection of eV Dark Matter via Infrared Spectroscopy

• DOI: 10.48550/arxiv.2208.05975
• Publication Date: 2022-11-22
• Authors: Taiki Bessho; Yuji Ikeda; Wen Yin
• Keywords: Cosmology and Nongalactic Astrophysics (astro-ph.CO); FOS: Physical sciences; Astrophysics - Astrophysics of Galaxies; 01 natural sciences; 7. Clean energy; High Energy Physics - Phenomenology; High Energy Physics - Phenomenology (hep-ph); Astrophysics of Galaxies (astro-ph.GA); 0103 physical sciences; Astrophysics - Instrumentation and Methods for Astrophysics; Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics - Cosmology and Nongalactic Astrophysics

Infrared spectroscopy has been developed significantly. In particular, infrared photons can be measured with high spectral and angular resolution in state-of-art spectrographs. They are sensitive to monochromatic photons due to the decay and annihilation of particles beyond the Standard Model, such as dark matter (DM), while insensitive to background photons that form a continuous spectrum. In this paper, we study the indirect detection of the DM decaying into infrared light using infrared spectrographs. In particular, we show that serious thermal and astrophysical noises can be overcome. As concrete examples, the Warm INfrared Echelle spectrograph to Realize Extreme Dispersion and sensitivity (WINERED) installed at the Magellan Clay 6.5m telescope and Near-Infrared Spectrograph (NIRSpec) at the James Webb Space Telescope (JWST) are discussed. We show that a few hours of measurements of a faint dwarf spheroidal galaxy with WINERED (NIRSpec-like spectrograph) in the Magellan telescope (JWST) can probe an axion-like particle DM in the mass range $m_ϕ=1.8 - 2.7\,$eV ($0.5-4\,$eV) with a photon coupling $g_{ϕγγ}\gtrsim 10^{-11}{\rm GeV}^{-1}$. Complemental approaches, taking advantage of the high resolutions, such as the measurement of the Doppler shift of the signal photon lines and the possible search of the DM decay around the Milky Way galaxy center with Infrared Camera and Spectrograph (IRCS) at 8.2m Subaru telescope, are also presented.<br/>v2: 27 pages, 4 figures, 3 tables. Based on the published version with additional typo corrections in the caption of Table 1 and within Figures 1 and 2 to match the main discussion<br/>