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arXiv 1403.7410hep-ph
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B --> pi l+ l-衰变的速率和不对称性

Rates and Asymmetries of B --> pi l+ l- Decays

Wei-Shu Hou, Masaya Kohda, Fanrong Xu

摘要:

LHCb实验观察到B+ --> pi+ mu+ mu-衰变,数据为1.0 fb^-1,这是第一次测量到味道改变的中性电流b --> d l+ l-衰变(l = e,mu)。基于QCD因子分解,在双轻子不变质量较小的运动学区域,我们给出了B -> pi l+ l-衰变的分支比、直接CP不对称性和同位旋不对称性的标准模型预言.我们发现,弱湮没的贡献增强了低l+ l对质量的直接CP不对称性。预期改进的测量,我们评估了B+ --> pi+ l+ l-可观测量与B 0--> pi- l+ nu和B+ --> K+ l+ l-结合时的效用,用于在未来确定CKM参数。

英文摘要:

The LHCb experiment observed B+ --> pi+ mu+ mu- decay with 1.0 fb^-1 data, which is the first measurement of a flavor changing neutral current b --> d l+ l- decay (l = e, mu). Based on QCD factorization, we give Standard Model predictions for the branching ratios, direct CP asymmetries, and isospin asymmetry for B --> pi l+ l- decays, in the kinematic region where the dilepton invariant mass is small. We find that the contribution from weak annihilation enhances the direct CP asymmetry for low l+ l- pair mass. Anticipating improved measurements, we assess the utility of B+ --> pi+ l+ l- observables, when combined with B0 --> pi- l+ nu and B+ --> K+ l+ l-, for determining CKM parameters in the future.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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