Observation of the Decay Λb0→Λc+τ−ν¯τ
Observation of the Decay Λb0→Λc+τ−ν¯τ
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腐烂的观察 Îb0âÎc Ïâν� Ï
DOI：
10.1103/physrevlett.128.191803
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发表时间：
2022
影响因子：
8.6
通讯作者：
Aidala, C. A.
中科院分区：
文献类型：
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作者：
Aaij, R.;Abdelmotteleb, A. S. W.;Beteta, C. Abellán;Abudinén, F.;Ackernley, T.;Adeva, B.;Adinolfi, M.;Afsharnia, H.;Agapopoulou, C.;Aidala, C. A.
利用LHCb实验在LHC质心能量为7和8 TeV时收集到的与积分光度相对应的数据样本，首次观测到具有显著性的半子-重子衰变。轻子在强子衰变中被重建为三个带电介子。测得比值K=B（Λb0→Λc+τ-ν¯τ）/B（Λb0→Λc+π-π+π-）为，其中第一不确定性为统计不确定性，第二不确定性为系统不确定性。分支分数B（Λb0→Λc+τ-ν¯τ）=(1.50±0.16±0.25±0.23)%，其中第三个不确定性来自于归一化通道的外部分支分数。推导出半光子分支分数R（Λc+）≡B（Λb0→Λc+τ-ν¯τ）/B（Λb0→Λc+μ-ν¯μ）的比值为，其中来自通道的外部分支分数的不确定性对最后一项有贡献。这一结果与标准模型预测一致。
The first observation of the semileptonic-baryon decay, with a significance of, is reported using a data sample corresponding toof integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. Thelepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+π-π+π-) is measured to be, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λb0→Λc+τ-ν¯τ)=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel. The ratio of semileptonic branching fractions R(Λc+)≡B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+μ-ν¯μ) is derived to be, where the external branching fraction uncertainty from the channelcontributes to the last term. This result is in agreement with the standard model prediction.