Positronium Quadrupole Interactions in Crystals

Abstract

Abstract It is shown that, due to the hyperfine interaction between the electron and the positron, positronium atoms in a crystal can acquire an effective quadrupole moment and a tensor polarizability. In such a case the effective quadrupolar interaction with intracrystalline fields leads to a quadrupolar splitting of the triplet level of positronium and also to an anisotropy of its magnetic quenching in the presence of an external magnetic field. The possibilities of observating this anisotropy experimentally are discussed.