Differential interaction of chiral β-particles with enantiomers

VESTER1 and Ulbricht2 invoked the parity-violating weak interaction as the cause of biological homochirality. They postulated that a stereoselective synthesis or decay of chiral molecules could be induced by the left circularly polarized bremsstrahlung; this small effect would then be amplified to full homochirality3–5. Despite much effort during the past thirty years, experimental results have been inconclusive and contradictory6–12. The aim of the study described here was more modest; we did not want to demonstrate differential synthesis or the decay of enantiomers bombarded by β-particles. Rather, using pulse-height spectroscopy, we examined the Cerenkov radiation emitted as β-particles pass through liquid chiral enantiomers. Our results show that helical electrons do distinguish between molecules of opposite chirality, and complement results reported in earlier publications in which differential decay6,13, positron annihilation14,15, scattering16,17 or other interactions18–20 were observed.