First Result for Dark Matter Search by WINERED.

Area of Science:

• Astronomy
• Cosmology
• Particle Physics

Background:

• The nature of dark matter remains a fundamental unsolved problem across multiple scientific disciplines.
• Previous searches for dark matter candidates have yielded no definitive results.

Purpose of the Study:

• To conduct the first dark matter search using a high-dispersion spectrograph (WINERED).
• To constrain the properties of dark matter, specifically its lifetime and photon coupling, by detecting photons from its decay.

Main Methods:

• Utilized the WINERED spectrograph on the 6.5m Magellan Clay telescope.
• Observed dwarf spheroidal galaxies Leo V and Tucana II using an object-sky-object nodding technique.
• Applied sky subtraction, Doppler shift analysis, and zero consistent flux data for background reduction.

Main Results:

• Established one of the most stringent limits on dark matter lifetime in the 1.8-2.7 eV mass range.
• Translated these limits to constraints on the photon coupling (g_{ϕγγ}) for axionlike particles.
• Derived bounds of g_{ϕγγ}≲(2-3)×10^{-11} GeV⁻¹ (or 10⁻¹⁰ GeV⁻¹) assuming specific dark matter profiles.

Conclusions:

• The study provides significant new constraints on dark matter properties, particularly for axionlike particles.
• The methodology demonstrates the potential of high-dispersion spectroscopy for dark matter searches.
• Future observations with improved techniques could further refine these limits and potentially reveal dark matter signals.