Electromagnetic mass splittings of mesons and baryons in the quark model

Abstract

Relations for the electromagnetic mass differences of mesons and baryons which can be derived from the quark model under various assumptions are critically reviewed and discussed in some detail. In particular, in the case of mesons, the mass dependent corrections arising from the spatial structure of mesons and which have been found necessary in the description of weak and electromagnetic decays in the quark model are examined and are found to be consistent with experimental data. It is found however that more accurate data on the K ∗ and the ϱ mass differences are needed to decide whether the spatial structure of all pseudoscalar and vector mesons is the same or whether it depends sensitively on the meson mass.