A Covariant Light-Front Model of Heavy Mesons within HQET

In this paper we construct a covariant light-front model of heavy mesons within the framework of heavy quark effective theory (HQET). The covariant model consists of the light-front heavy meson bound states constructed in the heavy quark limit with heavy quark symmetry and heavy quark effective theory as its basis. Within this model, the Isgur-Wise function and decay constants in the infinite quark mass limit can be evaluated in a very simple and the most general way. The results are ensured to be consistent with heavy quark symmetry. From the heavy-quark-limit bound states, we can further develop a systematic approach to calculate $1/m_Q$ corrections from the $1/m_Q$ expansion of QCD. This covariant model can serve as a quasi-first-principles description of heavy meson dynamics, namely, a phenomenological covariant bound state in the heavy quark limit which is consistent with heavy quark symmetry, plus a reliable first-principles computation of the $1/m_Q$ corrections in HQET in terms of the $1/m_Q$ expansion of the fundamental QCD theory.