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Register a new userNonfactorizable contributions to $B to D^{(*)} M$ decays
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While the factorization assumption works well for many two-body nonleptonic $B$ meson decay modes, the recent measurement of $bar Bto D^{(*)0}M^0$ with $M=pi$, $rho$ and $omega$ shows large deviation from this assumption. We analyze the $Bto D^{(*)}M$ decays in the perturbative QCD approach based on $k_T$ factorization theorem, in which both factorizable and nonfactorizable contributions can be calculated in the same framework. Our predictions for the Bauer-Stech-Wirbel parameters, $|a_2/a_1|= 0.43pm 0.04$ and $Arg(a_2/a_1)sim -42^circ$ and $|a_2/a_1|= 0.47pm 0.05$ and $Arg(a_2/a_1)sim -41^circ$, are consistent with the observed $Bto Dpi$ and $Bto D^*pi$ branching ratios, respectively. It is found that the large magnitude $|a_2|$ and the large relative phase between $a_2$ and $a_1$ come from color-suppressed nonfactorizable amplitudes. Our predictions for the ${bar B}^0to D^{(*)0}rho^0$, $D^{(*)0}omega$ branching ratios can be confronted with future experimental data.
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The decay amplitudes for anti-B0 -> Ds+ Ds- and anti-Bs0 -> D+ D- have no factorizable contributions. We suggest that dominant contributions to the decay amplitudes arise from two chiral loop contributions and one soft gluon emission contribution. Then we determine branching ratios BR(anti-B0 -> Ds+ Ds-) ~ 7E-5 and BR(anti-Bs0 -> D+ D-) ~ 1E-3.
We calculate tree-level contributions to the inclusive rare $bar B to X_{s(d)} , ell^+ell^-$ decays. At the partonic level they stem from the five-particle process $b to s(d) , q bar q , ell^+ell^-$, with $q in {u,d,s}$. While for $b to d$ transitions such five-body final states contribute at the same order in the Wolfenstein expansion compared to the three-body partonic decay, they are CKM suppressed in $b to s$ decays. In the perturbative expansion, we include all leading-order contributions, as well as partial next-to-leading order QCD and QED effects. In the case of the differential branching ratio, we present all results completely analytically in terms of polylogarithmic functions of at most weight three. We also consider the differential forward-backward asymmetry, where all except one interference could be obtained analytically. From a phenomenological point of view the newly calculated contributions are at the percent level or below.
We discuss the possibility to measure in present experiments, especially LHCb, the non leptonic decay branching ratio $B to D pi$, and emphasize phenomenological implications on $B to D l u$ semileptonic decay. We have estimated by lattice QCD the $D$ decay constant $f_{D}$ that parameterizes the $D$ emission contribution to the Class-III non leptonic decay $B^- to D^0 pi^-$. In addition, we provide a new estimate of the decay constants $f_{D_{s,q}}$ which read $f_{D_{s}}=252(3)$ MeV and $f_{D_{s}}/f_{D}=1.23(1)(1)$.
The e+e- annihilation data recorded with the BABAR detector has been used to study B^0 decays to Ds^(*)+ and D^*-$ mesons. The production fraction of inclusive Ds^(*)+ and the corresponding momentum spectra have been determined. Exclusive decays B^0 --> D^*- Ds^(*)+ have been identified with a partial reconstruction technique and their branching ratios have been measured. Fully reconstructed B^0 decays in the hadronic modes B^0 --> D^*- pi+ andB^0 --> D^*- rho+ have been also studied and the measurement of their absolute branching fractions is reported.
The observed strong phase difference of 30^{o} between I=(3/2) and I=(1/2) final states for the decay B to D Pi is analyzed in terms of rescattering like D^{∗}Pi to D Pi, etc. It is concluded that for the decay B^{o}to D^{+} Pi^{-} the strong phase is only about 10^{o}. Implications for the determination of sin(2 Beta + gamma) are discussed.
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