测量包含半轻子 Λ_{c}^{+}衰变的绝对分支比。

Measurement of the Absolute Branching Fraction of the Inclusive Semileptonic Λ_{c}^{+} Decay.

机构信息

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.

出版信息

Phys Rev Lett. 2018 Dec 21;121(25):251801. doi: 10.1103/PhysRevLett.121.251801.

DOI:10.1103/PhysRevLett.121.251801

PMID:30608802

Abstract

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.

摘要

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。