Search for solar axions produced in the p(d,3He)A reaction with Borexino detector
G. Bellini et al. (Borexino collaboration)
Phys. Rev. D 85, 092003
Published 4 May 2012
doi:10.1103/PhysRevD.85.092003 (preprint on arXiv)
A search for 5.5 MeV solar axions produced in the p+d→3He+A (5.5 MeV) reaction was performed using the Borexino detector. The Compton conversion of axions to photons, A+e→e+γ; the axioelectric effect, A+e+Z→e+Z; the decay of axions into two photons, A→2γ; and inverse Primakoff conversion on nuclei, A+Z→γ+Z, are considered. Model-independent limits on axion-electron (gAe), axion-photon (gAγ), and isovector axion-nucleon (g3AN) couplings are obtained: |gAe×g3AN|≤5.5×10−13 and |gAγ×g3AN|≤4.6×10−11 GeV−1 at mA<1 MeV (90% confidence level). These limits are 2–4 orders of magnitude stronger than those obtained in previous laboratory-based experiments using nuclear reactors and accelerators.