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In this paper we study the semileptonic decays of Bc-→(ηc,J/Ψ)l-vl. We first evaluate the Bc→(ηc,J/Ψ) transition form factors F0(q2), F+(q2), V(q2) and A0,1,2(q2) by employing the pQCD factorization approach, and then we calculate the branching ratios for all considered semileptonic decays. Based on the numerical results and the phenomenological analysis, we find that: (a) the pQCD predictions for the values of the Bc→ηc and Bc→J/Ψ transition form factors agree well with those obtained by using other methods; (b) the pQCD predictions for the branching ratios of the considered decays are Br(Bc-→ηc e-ve(μ-vμ)=(4.41-1.09+1.22)×10-3, Br(Bc-→ηcτ-vτ) =(1.37-0.34+0.37)×10-3, Br(Bc-→J/Ψ e-ve(μ-vμ)) =(10.03-1.18+1.33)×10-3, and Br(Bc-→J/Ψτ-vτ) =(2.92-0.34+0.40)×10-3; and (c) we also define and calculate two ratios of the branching ratios Rηc and RJ/Ψ, which will be tested by LHCb and the forthcoming Super-B experiments. 相似文献
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In this paper,we calculated the branching ratios and direct CP violation of the four B→Kπ decays with the inclusion of all currently known next-to-leading order(NLO) contributions by employing the perturbative QCD(pQCD) factorization approach.We found that(a) Besides the 10%enhancement from the NLO vertex corrections,the quark-loops and magnetic penguins,the NLO contributions to the form factors can provide an additional~15%enhancement to the branching ratios,and lead to a very good agreement with the data;(b) The NLO pQCD predictions are A_(CP)~(dir)(B~0→K~+π~0)=(-6.5±3.1)%and A_(CP)~(dir)(B~+→K~+π~0)=(2.2±2.0)%,become well consistent with the data due to the inclusion of the NLO contributions. 相似文献
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