共查询到20条相似文献,搜索用时 15 毫秒
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用微扰QCD对B(s) →Фρ 衰变进行了研究,考虑了因子化和非因子化图的贡献,得出了B(s) →Фρ 衰变的分支比以及纵向极化衰变、横向极化衰变之比,所得到的结果与现在的实验数据吻合. 相似文献
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通过构造适当的关联函数,计算B→π跃迁形状因子f+Bπ(q2),~fBπ(q2)和标量形状因子f0(q2),从而就能研究轻子质量对B0→π-l+~vl(l=e,μ,τ)衰变过程的影响.首次分别计算B0→π-e+~ve,B0→π-μ+~vμ,B0→π-τ+~vτ衰变过程的分支比,并发现轻子质量me,mμ可以忽略,但重轻子质量mτ不能忽略,它对分支比计算有一定的贡献.把计算结果与最近的实验数据进行比较,发现理论结果与实验数据基本符合. 相似文献
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通过构造适当的关联函数,计算B→π跃迁形状因子fB+π(q2),fBπ(q2)和标量形状因子f0(q2),从而就能研究轻子质量对B0→π-+ν(l=e,μ,τ)衰变过程的影响.首次分别计算B0→π-e+νe,B0→π-μ+νμ,B0→π-τ+ντ衰变过程的分支比,并发现轻子质量me,mμ可以忽略,但重轻子质量mτ不能忽略,它对分支比计算有一定的贡献.把计算结果与最近的实验数据进行比较,发现理论结果与实验数据基本符合. 相似文献
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We have analyzed the D^0→π^+π^- decay with α_s corrections in quantum chromodynamic (QCD) factorization and with the soft-gluon corrections in the light cone QCD sum rules. The soft-gluon effects are firstly calculated in the decay channel. The results show that once the factorization contributions, the α_s corrections, and the soft-gluon effects are all considered, we can satisfactorily explain the experimental data in the decay channel. 相似文献
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We have investigated the role of soft-gluon exchanges in B→ππ,using the light-cone sum rules in quantum chromodynamics,The calculations are carried out not only for the tree operators but also for the penguin operators.We conclude that soft-gluon exchanges contribute to the decay amplitudes,noticeably on some decay channels,and thus cannot be neglected. 相似文献
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Based on the assumption of a two-quark structure of the scalar meson f0(980) ,we calculate the branching ratios and CP-violating asymmetries for the four B → f0(980) π and B → f0(980) η^(') decays by employing the perturbative QCD(pQCD) factorization approach. The leading order pQCD predictions for branching ratios are,Br(B^-→ f0(980) π^-) ~ 2.5×10^-6,Br(Bˉ^0 → f0(980) π^0) ~ 2.6×10^-7,Br(Bˉ^0 → f0(980) η) ~ 2.5×10^-7 and Br(Bˉ^0 → f0(980) η ) ~ 6.7×10^-7,which are consistent with both the QCD factorization predictions and the experimental upper limits. 相似文献
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In this article, we calculate the branching ratios of B→K0^* (1430)K decays by employing the pertur-bative QCD (pQCD) approach at leading order. We perform the evaluations in the two scenarios for the scalar meson spectrum. We find that (i) The leading order pQCD predictions for the branching ratio Br(B^+→K^+K0^*(1430)^0)are in good agreement with the experimental upper limit in both scenarios, while the pQCD predictions for other considered B→K0^*(1430)K decay modes are also presented and will be tested by the LHC experiments; (ii) The annihilation contributions play an important role in these considered decays, for B^0→K0^*(1430)^±K^± decays,for example,which are found to be (1-4)×10^-6. 相似文献
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在标准模型中,稀有衰变道B+→D+sK*0只有通过纯湮没图才可以发生.这样这个衰变道的分支比很小.利用基于kT?因子化的微扰方法给出分支比的预测,发现它在10-8的量级上.这个衰变道估计在将来的LHC上得到测量,对检验标准模型以及探寻新物理有着重要的意义. 相似文献
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利用北京谱仪 (BES -Ⅰ )在北京正负电子对撞机 (BEPC)e+ e-质心系能量为 4 .0 3GeV处采集的积分亮度为 2 2 .3pb-1的数据 ,研究了D0 →K0sπ+ π-,D0 →K0sK+ K-的衰变及其末态的共振结构 .实验测得D0 →K0sπ+ π-过程的分支比为 (5 .32± 0 .5 3± 0 .4 0 ) % ;D0 →K -π+ ,D0 →K0 ρ0 和D0 →K0s(π+ π-)non resonance过程的分支比分别为 (6 .0 5± 0 .32± 0 .4 9) % ,(1.17± 0 .17± 0 .13) %和 (1.35± 0 .2 2± 0 .17) % ;测得D0 →K0sK+ K-,D0 →K0 和D0 → K0 (K+ K-) non 的分支比分别为 (1.0 4± 0 .2 4± 0 .16 ) % ,(1.12± 0 .34± 0 .15 ) %和 (0 .2 7± 0 .13±0 .0 3) % . 相似文献
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利用北京谱仪(BES–Ⅰ)在北京正负电子对撞机(BEPC)e+e–质心系能量为4.03GeV处采集的积分亮度为22.3pb–1的数据,研究了D0→K0sπ+π–,D0→K0sK+K–的衰变及其末态的共振结构.实验测得D0→K0sπ+π–过程的分支比为(5.32±0.53±0.40)%;D0→K–π+,D0→K0ρ0和D0→K0s(π+π–)non resonance过程的分支比分别为(6.05±0.32±0.49)%,(1.17±0.17±0.13)%和(1.35±0.22±0.17)%;测得D0→K0sK+K–,D0→K0和D0→K0(K+K–)non?的分支比分别为(1.04±0.2?4±0?.16)%,(1.12±0.34±0.15)%和(0.27±0.13±0.03)%. 相似文献
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In this article, we calculate the contribution from the nonfactorizable soft hadronic matrix element to the decay B^0→Xc1π^0 with the light-cone quantum chromo-dynamic (QCD) sum rules. The numerical results show that its contribution is rather large and should not be neglected. The total amplitudes lead to a branching fraction which is in agreement with the experimental data marginally. 相似文献
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