The CKM suppressed B(B_s) rightarrow bar{D}{(s)}P, bar{D}{(s)}V, bar{D}{(s)}*P, bar{D}{(s)}*V decays in the perturbative QCD approach

doi:10.1088/0954-3899/37/1/015002

The CKM suppressed $B(B_s) \rightarrow \bar{D}_{(s)}P\hbox{,}\, \bar{D}_{(s)}V\hbox{,} \bar{D}_{(s)}^P\hbox{,}\, \bar{D}_{(s)}^V$ decays in the perturbative QCD approach

Hao Zou et al 2010 J. Phys. G: Nucl. Part. Phys. 37 015002 (21pp) doi: 10.1088/0954-3899/37/1/015002

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Hao Zou¹, Run-Hui Li^1,2, Xiao-Xia Wang¹ and Cai-Dian Lü^1,3
¹ Institute of High Energy Physics, PO Box 918(4), Beijing 100049, People's Republic of China
² School of Physics, Shandong University, Jinan 250100, People's Republic of China
³ Theoretical Physics Center for Science Facilities, Beijing 100049, People's Republic of China
E-mail: zouhao@ihep.ac.cn, lirh@ihep.ac.cn, xxwang@ihep.ac.cn and lucd@ihep.ac.cn

Abstract. Although the two-body charmed decays $B_{(s)} \rightarrow \bar{D}_{(s)}^{(*)}P$ and $\bar{D}_{(s)}^{(*)}V$ , where P (V) denotes a light pseudoscalar (vector) meson, are Cabbibo–Kobayashi–Maskawa (CKM) suppressed compared with the B_(s) → D^(*)_(s)P and D^(*)_(s)V decays, they are important in the CKM angle γ = phi ₃ extraction method. We investigated these decays in the perturbative QCD approach to the leading order of m_D/m_B and Λ_QCD/m_D expansion. We find that the nonfactorizable emission diagrams and the annihilation diagrams are not negligible in many of these channels. The numerical results show that most channels have branching ratios with an order of 10⁻⁶ or 10⁻⁷. The ratio needed for the CKM angle γ extraction is estimated as $r = \frac{|A(B^- \rightarrow \bar{D}^0 K^-)|}{|A(B^- \rightarrow D^0 K^-)|} = 0.092_{-0.003-0.003}^{+0.012+0.003},$ which is too small for the experiments. Some of the $B_{(s)}\rightarrow \bar{D}_{(s)}^*V$ decays have a very large transversely polarized contribution that can reach 80%.