Nonleptonic B decays into a charmed tensor meson

Abstract

In the framework of the factorization and the heavy quark effective theory, $B\to D_2^{\ast }\pi$ modes are analyzed. We adopt the result from the QCD sum rule calculation for the hadronic matrix elements at leading order of ${\Lambda }_{\mathrm{QCD}}/m_Q$ and ${\alpha }_s$. The QCD sum rule results are well compatible with the current data, with the prediction on the branching ratios $\text{calB}({\text{Bbar}}^0\to D_2^{\ast +}{\pi }^{-})=8.94\times 10^{-4}$ and $\text{calB}(B^{-}\to D_2^{\ast 0}{\pi }^{-})=9.53\times 10^{-4}$ for $N_C^{\mathrm{eff}}=2$. We give constraints on the interception $\tau (1)$ and the slope parameter ${\rho }^2$ of the leading Isgur-Wise function from the experimental bounds. It is argued that the observation of nonzero $\text{calB}({\text{Bbar}}^0\to D_2^{\ast 0}{\pi }^0)$ directly measures the nonfactorizable effets.

Comments: More discussions, references added, to appear in Eur. Phys. J. C