Polarized electrons see mirrored molecules differently

Amino acids and other biologically important molecules can be distinguished from their mirror images; the two chiral forms, designated as right-handed and left-handed, are called enantiomers. For reasons that remain unknown, only one of the two possible enantiomers is found in living organisms. Longitudinally polarized electrons, too, exist in a pair of mirror-related forms. The right-handed electrons with spin and momentum parallel are distinct from left-handed electrons with spin and momentum antiparallel. The difference is of more than academic interest; in particle physics the weak interactions break parity (inversion) symmetry, and electrons produced in beta decay are predominantly left-handed. Could the preferred handedness chosen by the weak interactions be related to the preferred handedness in living organisms? A necessary (but not sufficient) condition would be that longitudinally polarized electrons can react differently with mirror-related enantiomers. To test that requirement, Joan Dreiling and Timothy Gay (University of Nebraska–Lincoln) studied dissociation reactions...