Feasibility Study for Measuring Geomagnetic Conversion of Solar Axions to X-rays in Low Earth Orbits

TL;DR

This study evaluates the potential of satellite-based measurements of geomagnetic conversion of solar axions into X-rays to improve constraints on axion-photon coupling, considering realistic orbital and environmental factors.

Contribution

It provides a detailed computational model for GECOSAX detection feasibility using actual satellite data and realistic Earth magnetic field and atmospheric models.

Findings

Potential to set a new limit on axion-photon coupling g_{aγ}

Demonstrates feasibility with existing satellite data and realistic assumptions

Significantly improves upon current laboratory sensitivities

Abstract

We present a detailed computation of the expected rate for Geomagnetic Conversion of Solar Axions to X-rays (GECOSAX) along the orbit of an x-ray satellite. We use realistic satellite orbits and propagation in time. A realistic model for the Earth's magnetic field, which properly accounts for its spatial non-uniformity, is used. We also account for the effect of the Earth's atmosphere on the propagation of x-rays in our calculation of axion-photon conversion probability. To estimate possible sensitivities to the axion-photon coupling g_{a\gamma}, we use an actual measurement of the expected backgrounds by the SUZAKU satellite. Assuming a detector area of 10^3 cm^2 and about 10^6 s of data, we show that a 2 \sigma limit of g_{a\gamma} < (4.7-6.6) times 10^{-11} GeV^{-1} from GECOSAX is achievable, for axion masses m_a<10^{-4} eV. This significantly exceeds current laboratory sensitivities to g_{a\gamma}.