What can a relativistic quark model tell us about charmed mesons?

摘要

A relativistic quark model is extended to incorporate chiral and gaugesymmetries. We obtain the DD*pi and DD*gamma couplings and find that the ratioGamma(D*0->D0pi0)/Gamma(D*0->D0gamma) constrains the charm-quark mass close to1.45 GeV. Large 1/mc corrections appear in the heavy-quark contribution to theDD*gamma coupling. The model is extended further to describe seven excited Dmeson states. We find that semileptonic B decays into the ground and excited Dmeson states do not account for the total semileptonic decay width of the B0.The nonresonant contributions to the processes B0->D(*)pi+ell+nu appear to belarge enough to account for the discrepancy.