Mass breaking in a relativistic quark model for mesons

Abstract

We study symmetry breaking via quark mass differences in a relativistic quark model where mesons are built from heavy ( m > 3 GeV) spin 1 2 ) quarks and antiquarks. The meson (squared-)mass differences are linearly related to the number of strange, charmed, etc. quarks in the mesons. We show that the previously assumed SU n symmetry of the mesonic couplings holds, i.e., quark mass differences only show up in the masses of the external particles, not in the three meson vertex itself.