$D_{sJ}(2860)$ From The Semileptonic Decays Of $B_s$ Mesons

Abstract

In the framework of heavy quark effective theory, the leading order Isgur-Wise form factors relevant to semileptonic decays of the ground state $\bar{b}s$ meson $B_{s}$ into orbitally excited $D$-wave $\bar{c}s$ mesons, including the newly observed narrow $D^{*}_{s1}(2860)$ and $D^{*}_{s3}(2860)$ states by the LHCb Collaboration, are calculated with the QCD sum rule method. With these universal form factors, the decay rates and branching ratios are estimated. We find that the decay widths are $\Gamma(B_s\rightarrow D^{*}_{s1}\ell\bar{\nu}) =1.25^{+0.80}_{-0.60}\times10^{-19} \mbox{GeV}$, $\Gamma(B_s\rightarrow D^{'}_{s2}\ell\bar{\nu}) =1.49^{+0.97}_{-0.73}\times10^{-19} \mbox{GeV}$, $\Gamma(B_s\rightarrow D_{s2}\ell\bar{\nu}) =4.48^{+1.05}_{-0.94}\times10^{-17} \mbox{GeV}$, and $\Gamma(B_s\rightarrow D^{*}_{s3}\ell\bar{\nu}) = 1.52^{+0.35}_{-0.31}\times10^{-16} \mbox{GeV}$. The corresponding branching ratios are $\mathcal {B}(B_s\rightarrow D^{*}_{s1}\ell\bar{\nu}) =2.85^{+1.82}_{-1.36}\times 10^{-7}$, $\mathcal {B}(B_s\rightarrow D^{'}_{s2}\ell\bar{\nu}) =3.40^{+2.21}_{-1.66}\times 10^{-7}$, $\mathcal {B}(B_{s}\rightarrow D_{s2}\ell\bar{\nu}) =1.02^{+0.24}_{-0.21}\times 10^{-4}$, and $\mathcal {B}(B_s\rightarrow D^{*}_{s3}\ell\bar{\nu}) = 3.46^{+0.80}_{-0.70}\times 10^{-4}$. The decay widths and branching ratios of corresponding $B^{*}_{s}$ semileptonic processes are also predicted.