Spin-orbit inversion of excited heavy quark mesons

The mesonic heavy quark spin multiplets with s(l)(pi l) = 1/2(+) and 3/2(+) are expected to be the lowest-lying excitations above the pseudoscaler and vector ground states with s(l)(pi l) = 1/2(-). I show that for charm and bottom these multiplets are probably inverted, with the 2(+) and 1(+) states with s(l)(pi l) = 3/2(+) about 150 MeV below the 1(+) and 0(+) states with s(l)(pi l) = 1/2(+). If verified, such an inversion would both support the expectation that confinement has no dynamical spin-dependence and indicate that heavy-and light-quark systems may be characterized by the same effective low-energy degrees of freedom. As an important by-product, this work establishes the dynamics of the strange quark as a critical link between heavy-and Light-quark hadrons, justifying efforts toward a much more complete experimental and theoretical understanding of strange mesons and baryons and of strange quarkonia. [S0556-2821(98)00505-0].