The search for solar axions in the CAST experiment

TL;DR

The CAST experiment searches for solar axions by converting them into detectable X-ray photons using a strong magnetic field, setting new limits on axion properties and extending sensitivity to higher masses.

Contribution

This paper reports the first results from the CAST experiment, including new upper bounds on axion-photon coupling and the implementation of buffer gas to explore higher axion masses.

Findings

Set an upper limit of g_{aγ} < 0.9×10^{-10} GeV^{-1} for axion masses below 0.02 eV.

Extended sensitivity to axion masses up to 0.8 eV using buffer gas.

Collected data with a 9 Tesla magnet and X-ray detectors at CERN.

Abstract

The CAST (CERN Axion Solar Telescope) experiment at CERN searches for solar axions with energies in the keV range. It is possible that axions are produced in the core of the sun by the interaction of thermal photons with virtual photons of strong electromagnetic fields. In this experiment, the solar axions can be reconverted to photons in the transversal field of a 9 Tesla superconducting magnet. At both ends of the 10m-long dipole magnet three different X-ray detectors were installed, which are sensitive in the interesting photon energy range. Preliminary results from the analysis of the 2004 data are presented: g$_{a\gamma}<0.9\times10^{-10}$ GeV$^{-1}$ at 95% C.L. for axion masses m$_{a} <$ 0.02 eV. At the end of 2005, data started to be taken with a buffer gas in the magnet pipes in order to extend the sensitivity to axion masses up to 0.8 eV.