Heavy-quark spin symmetry andDmesons

Abstract
The implications of heavy-quark spin symmetry for P-state mesons with one heavy quark are discussed. In particular, we have derived the mass relation mD1*−mD0=52(mD2*−mD1) for the four P-state mesons. We have shown that the E1 transition decay D1(2420)→D+γ is a prediction of the above symmetry and as such should be tested experimentally. We predict mD1*=2.29 GeV and mD0=2.19 GeV in the model in which the spin-dependent potential is taken to be a one-gluon-exchange potential. In the second model, with the Cornell potential in the Dirac Hamiltonian, we obtain mD1*=2.01 GeV and mD0=1.91 GeV.