Nuclear β-decay and the origin of biomolecular chirality

The origin of homochirality in terrestrial life has long been debated1. Asymmetric decomposition of racemic mixtures of bio-molecules by longitudinally polarized β-rays has been described as a possible mechanism for inducing optical activity2. Here I present an extension of former estimates given by Hegstrom3 with respect to this process. I derive the energy dependence and sign of the relative asymmetries in radiolysis cross-sections for both β+- and β–radiation, and the connection of these cross-sections with the decomposition rate constants. In the light of the amplification model devised by Kondepudi and Nelson4–7, I compare the chiral selectivity of β-rays with that of weak neutral current effects in handed molecules8,9.I argue that the exceptional prebiotic conditions required do not favour asymmetric β-radio-lysis as the selector of the exclusive signature of optical activity in living nature.