Covariant and heavy quark symmetric quark models

There exist relativistic quark models (potential or MIT bag) which satisfy the heavy quark symmetry (HQS) relations among meson decay constants and form factors. A covariant construction of the momentum eigenstates, developed here, can correct for spurious center-of-mass motion contributions. The proton form factor and M1 transitions in quarkonia are calculated. An explicit expression for the Isgur-Wise function is found and model-determined deviations from HQS are studied. All results depend on the model parameters only. No additional ad hoc assumptions are needed.