Pseudoscalar Conversion and X-rays from the Sun

Abstract

We investigate the detection of a pseudoscalar $\varphi$ that couples electromagnetically via an interaction $\frac{1}{4}g\varphi F\tilde{F}$. In particular, we focus on the conversion of pseudoscalars produced in the sun's interior in the presence of the sun's external magnetic dipole field and sunspot-related magnetic fields. We find that the sunspot approach is superior. Measurements by the SXT on the Yohkoh satellite can measure the coupling constant down to $g=0.5$--$1\times 10^{-10}\mathrm{Ge}{\mathrm{V}}^{-1}$, provided the pseudoscalar mass $m<7\times 10^{-6}$eV, which makes it competitive with other astrophysical approaches.

Comments: 15 pages, RevTex file. Figures available upon request to Carlson@physics.harvard.edu. (please include full mailing address in request). Submitted to Physics Letters B