Property of chiral scalar and axial-vector mesons in heavy-light quark systems

摘要

Recently we have proposed a new level-classification scheme of hadrons with a manifestly covariant framework. In this scheme the requirement of chiral symmetry on the light quark leads to a prediction of existence of new type of scalars X{sub}B, X{sub}D and axial-vectors X{sub}(B{sup}*), X{sub}(D{sup}*) as the chiral partners of ground state pseudoscalar B, D and vector B{sup}*, D{sup}* mesons, respectively. They belong to "relativistic S-wave states," and are discriminated from the conventional P-wave mesons with j{sub}q = 1/2 appearing in the heavy quark effective theory. In this talk we examine the properties of these chiral mesons: The mass-splittings between the respective chiral partners are predicted to be equal, and the decay widths of one pion emission of X{sub}B, X{sub}D, X{sub}(B{sup}*) and X{sub}(D{sup}*) are to take the same value due to both chiral and heavy quark symmetries. Some experimental indications for existence of X{sub}B and X{sub}(D{sup}*) are also given, which are consistent with the above prediction.