Search for spin effect in positron interaction with optically active camphor

Summary The depolarization, relative to the direction of a magnetic field, which accompanies the slowing-down of positrons in the two enantiomers of camphor, down to the positronium formation energy, has been found to be greater (27%) in L-camphor. The measuring method was based on the Ps relative yield, in the magnetic field, in triplet and singlet state. All other annihilation features, as well as the intrinsic properties of Ps once formed, do not display significant differences between the two enantiomers. This work was supported by INFM (Consorzio Nazionale di Fisica della Materia).