  We investigate the properties of new scalar X_B, X_D and axial-vector X_B*,
X_D* mesons, which are recently predicted, in the covariant
meson-classification scheme, to exist as the partners of ground-state
pseudoscalar B, D and vector B*, D* mesons, respectively, realizing a linear
representation of chiral symmetry for the light quark component in
heavy-light-quark meson system. The mass splittings between the respective
chiral partners are shown to be equal, and the decay widths of one pion
emission of X_B, X_D, X_B* and X_D* become to have a common value, due to
chiral and heavy quark symmetry.
