Searching for Axionlike Particles with X-Ray Observations of Alpha Centauri.

Area of Science:

• Particle astrophysics
• Stellar astrophysics
• High-energy physics

Background:

• Axionlike particles (ALPs) are hypothetical particles that can be produced in stellar cores.
• ALPs interact with electromagnetic fields and electrons, with masses typically between 0.1 and 10 keV.
• These particles can be gravitationally trapped in stellar orbits and decay into two photons, producing monochromatic X-ray lines.

Purpose of the Study:

• To search for gravitationally trapped ALPs decaying into photons in the Alpha Centauri binary system.
• To establish new stringent limits on ALP interactions, particularly ALP-photon and ALP-electron couplings.
• To utilize sensitive X-ray detectors like Chandra and eROSITA for this search.

Main Methods:

• Observing the Alpha Centauri binary system with sensitive X-ray detectors.
• Analyzing X-ray data in the energy range of 0.2 keV to 10 keV for monochromatic line signals.
• Comparing observed data with theoretical predictions for ALP decay into photons.

Main Results:

• No significant ALP decay signals were detected in the observed energy range.
• The study established the most stringent limits on ALP interactions to date.
• Improved limits on ALP-photon coupling (g_aγγ) by up to 2 orders of magnitude at 2 keV for ALP-electron coupling (g_aee) ≤ 10⁻¹⁵, with even tighter constraints for larger g_aee.

Conclusions:

• The null results place significant constraints on the properties and interactions of axionlike particles.
• This research advances our understanding of fundamental physics by probing exotic particle interactions in astrophysical environments.
• The findings highlight the potential of X-ray astronomy in searching for new physics beyond the Standard Model.