Institute of High Energy Physics, Beijing 100049, People's Republic of China.
G.I. Budker Institute of Nuclear Physics SB RAS (BINP), Novosibirsk 630090, Russia.
Phys Rev Lett. 2018 Dec 21;121(25):251801. doi: 10.1103/PhysRevLett.121.251801.
Using a data sample of e^{+}e^{-} collisions corresponding to an integrated luminosity of 567 pb^{-1} collected at a center-of-mass energy of sqrt[s]=4.6 GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic Λ_{c}^{+} decay with a double-tag method. We obtain B(Λ_{c}^{+}→Xe^{+}ν_{e})=(3.95±0.34±0.09)%, where the first uncertainty is statistical and the second systematic. Using the known Λ_{c}^{+} lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons (D^{0} and D^{+}), we obtain the ratio of the inclusive semileptonic decay widths Γ(Λ_{c}^{+}→Xe^{+}ν_{e})/Γover ¯=1.26±0.12.
利用 BESIII 探测器在质心系能量为 sqrt[s]=4.6 GeV 下采集的对应于 567 pb^{-1}积分亮度的 e^{+}e^{-}碰撞数据样本，我们采用双标记方法测量了包含性半轻子 Λ_{c}^{+}衰变的绝对分支比。我们得到 B(Λ_{c}^{+}→Xe^{+}ν_{e})=(3.95±0.34±0.09)%，其中第一个不确定度是统计不确定度，第二个是系统不确定度。利用已知的 Λ_{c}^{+}寿命和非奇异重子介子（D^{0} 和 D^{+}）的电荷平均半轻子衰变宽度，我们得到包含性半轻子衰变宽度 Γ(Λ_{c}^{+}→Xe^{+}ν_{e})/Γover ¯=1.26±0.12。
