Strong decays of heavy-light mesons in a chiral quark model

Abstract

We carry out a systematic study of the heavy-light meson strong decays in a chiral quark model. For the $S$-wave vectors [${D}^{*}(2007)$, ${D}^{*\ifmmode\pm\else\textpm\fi{}}(2010)$], $P$-wave scalars [${D}_{0}^{*}(2400)$, ${B}_{0}^{*}(5730)$], and tensors [${D}_{2}^{*}(2460)$, ${D}_{s2}^{*}(2573)$], we obtain results in good agreement with the experimental data. For the axial vectors ${D}_{1}(2420)$ and ${D}_{1}^{\ensuremath{'}}(2430)$, a state mixing scheme between $1^{1}P_{1}$ and $1^{3}P_{1}$ is favored with a mixing angle $\ensuremath{\phi}\ensuremath{\simeq}\ensuremath{-}(55\ifmmode\pm\else\textpm\fi{}5)\ifmmode^\circ\else\textdegree\fi{}$, which is consistent with previous theoretical predictions. The same mixing scheme also applies to ${D}_{s1}(2460)$ and ${D}_{s1}(2536)$ that accounts for the narrow width of the ${D}_{s1}(2536)$ and its dominant decay into ${D}^{*}K$. For ${B}_{1}(5725)$ and ${B}_{1}^{\ensuremath{'}}(5732)$, such a mixing explains well the decay width of the former but leads to an even broader ${B}_{1}^{\ensuremath{'}}(5732)$. Predictions for the strange-bottom axial vectors are also made. For the undetermined meson ${D}^{*}(2640)$, we find that they fit well in the radially excited state $2^{3}S_{1}$ according to its decay mode. The newly observed ${D}_{sJ}^{*}(2860)$ strongly favors the $D$-wave excited state $1^{3}D_{3}$. For ${D}_{sJ}^{*}(2632)$ and ${D}_{sJ}^{*}(2690)$, we find they are difficult to fit in any ${D}_{s}$ excitations in that mass region, if the experimental data are accurate. Theoretical predictions for decay modes of those unobserved states as multiplets of $2S$ and $1D$ waves are also presented, which should be useful for the further experimental search for those states.