测量 Λₑ⁺→Λe⁺νₑ 的绝对分支比。

Measurement of the Absolute Branching Fraction for Λ_{c}^{+}→Λe^{+}ν_{e}.

作者信息

Ablikim M, Achasov M N, Ai X C, Albayrak O, Albrecht M, Ambrose D J, Amoroso A, An F F, An Q, Bai J Z, Baldini Ferroli R, Ban Y, Bennett D W, Bennett J V, Bertani M, Bettoni D, Bian J M, Bianchi F, Boger E, Boyko I, Briere R A, Cai H, Cai X, Cakir O, Calcaterra A, Cao G F, Cetin S A, Chang J F, Chelkov G, Chen G, Chen H S, Chen H Y, Chen J C, Chen M L, Chen S J, Chen X, Chen X R, Chen Y B, Cheng H P, Chu X K, Cibinetto G, Dai H L, Dai J P, Dbeyssi A, Dedovich D, Deng Z Y, Denig A, Denysenko I, Destefanis M, De Mori F, Ding Y, Dong C, Dong J, Dong L Y, Dong M Y, Dou Z L, Du S X, Duan P F, Fan J Z, Fang J, Fang S S, Fang X, Fang Y, Fava L, Fedorov O, Feldbauer F, Felici G, Feng C Q, Fioravanti E, Fritsch M, Fu C D, Gao Q, Gao X L, Gao X Y, Gao Y, Gao Z, Garzia I, Goetzen K, Gong W X, Gradl W, Greco M, Gu M H, Gu Y T, Guan Y H, Guo A Q, Guo L B, Guo Y, Guo Y P, Haddadi Z, Hafner A, Han S, Hao X Q, Harris F A, He K L, Held T, Heng Y K, Hou Z L, Hu C, Hu H M, Hu J F, Hu T, Hu Y, Huang G M, Huang G S, Huang J S, Huang X T, Huang Y, Hussain T, Ji Q, Ji Q P, Ji X B, Ji X L, Jiang L W, Jiang X S, Jiang X Y, Jiao J B, Jiao Z, Jin D P, Jin S, Johansson T, Julin A, Kalantar-Nayestanaki N, Kang X L, Kang X S, Kavatsyuk M, Ke B C, Kiese P, Kliemt R, Kloss B, Kolcu O B, Kopf B, Kornicer M, Kuehn W, Kupsc A, Lange J S, Lara M, Larin P, Leng C, Li C, Li Cheng, Li D M, Li F, Li F Y, Li G, Li H B, Li J C, Li Jin, Li K, Li K, Li Lei, Li P R, Li T, Li W D, Li W G, Li X L, Li X M, Li X N, Li X Q, Li Z B, Liang H, Liang Y F, Liang Y T, Liao G R, Lin D X, Liu B J, Liu C X, Liu D, Liu F H, Liu Fang, Liu Feng, Liu H B, Liu H H, Liu H H, Liu H M, Liu J, Liu J B, Liu J P, Liu J Y, Liu K, Liu K Y, Liu L D, Liu P L, Liu Q, Liu S B, Liu X, Liu Y B, Liu Z A, Liu Zhiqing, Lou X C, Lu H J, Lu J G, Lu Y, Lu Y P, Luo C L, Luo M X, Luo T, Luo X L, Lyu X R, Ma F C, Ma H L, Ma L L, Ma Q M, Ma T, Ma X N, Ma X Y, Maas F E, Maggiora M, Mao Y J, Mao Z P, Marcello S, Messchendorp J G, Min J, Mitchell R E, Mo X H, Mo Y J, Morales Morales C, Muchnoi N Yu, Muramatsu H, Nefedov Y, Nerling F, Nikolaev I B, Ning Z, Nisar S, Niu S L, Niu X Y, Olsen S L, Ouyang Q, Pacetti S, Pan Y, Patteri P, Pelizaeus M, Peng H P, Peters K, Pettersson J, Ping J L, Ping R G, Poling R, Prasad V, Qi H R, Qi M, Qian S, Qiao C F, Qin L Q, Qin N, Qin X S, Qin Z H, Qiu J F, Rashid K H, Redmer C F, Ripka M, Rong G, Rosner Ch, Ruan X D, Santoro V, Sarantsev A, Savrié M, Schoenning K, Schumann S, Shan W, Shao M, Shen C P, Shen P X, Shen X Y, Sheng H Y, Song W M, Song X Y, Sosio S, Spataro S, Sun G X, Sun J F, Sun S S, Sun Y J, Sun Y Z, Sun Z J, Sun Z T, Tang C J, Tang X, Tapan I, Thorndike E H, Tiemens M, Ullrich M, Uman I, Varner G S, Wang B, Wang B L, Wang D, Wang D Y, Wang K, Wang L L, Wang L S, Wang M, Wang P, Wang P L, Wang S G, Wang W, Wang W P, Wang X F, Wang Y D, Wang Y F, Wang Y Q, Wang Z, Wang Z G, Wang Z H, Wang Z Y, Weber T, Wei D H, Wei J B, Weidenkaff P, Wen S P, Wiedner U, Wolke M, Wu L H, Wu Z, Xia L, Xia L G, Xia Y, Xiao D, Xiao H, Xiao Z J, Xie Y G, Xiu Q L, Xu G F, Xu L, Xu Q J, Xu Q N, Xu X P, Yan L, Yan W B, Yan W C, Yan Y H, Yang H J, Yang H X, Yang L, Yang Y, Yang Y X, Ye M, Ye M H, Yin J H, Yu B X, Yu C X, Yu J S, Yuan C Z, Yuan W L, Yuan Y, Yuncu A, Zafar A A, Zallo A, Zeng Y, Zeng Z, Zhang B X, Zhang B Y, Zhang C, Zhang C C, Zhang D H, Zhang H H, Zhang H Y, Zhang J J, Zhang J L, Zhang J Q, Zhang J W, Zhang J Y, Zhang J Z, Zhang K, Zhang L, Zhang X Y, Zhang Y, Zhang Y H, Zhang Y N, Zhang Y T, Zhang Yu, Zhang Z H, Zhang Z P, Zhang Z Y, Zhao G, Zhao J W, Zhao J Y, Zhao J Z, Zhao Lei, Zhao Ling, Zhao M G, Zhao Q, Zhao Q W, Zhao S J, Zhao T C, Zhao Y B, Zhao Z G, Zhemchugov A, Zheng B, Zheng J P, Zheng W J, Zheng Y H, Zhong B, Zhou L, Zhou X, Zhou X K, Zhou X R, Zhou X Y, Zhu K, Zhu K J, Zhu S, Zhu S H, Zhu X L, Zhu Y C, Zhu Y S, Zhu Z A, Zhuang J, Zotti L, Zou B S, Zou J H

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. 2015 Nov 27;115(22):221805. doi: 10.1103/PhysRevLett.115.221805. Epub 2015 Nov 25.

DOI:10.1103/PhysRevLett.115.221805

PMID:26650293

Abstract

We report the first measurement of the absolute branching fraction for Λ_{c}^{+}→Λe^{+}ν_{e}. This measurement is based on 567 pb^{-1} of e^{+}e^{-} annihilation data produced at sqrt[s]=4.599 GeV, which is just above the Λ_{c}^{+}Λ[over ¯]{c}^{-} threshold. The data were collected with the BESIII detector at the BEPCII storage rings. The branching fraction is determined to be B(Λ{c}^{+}→Λe^{+}ν_{e})=[3.63±0.38(stat)±0.20(syst)]%, representing a significant improvement in precision over the current indirect determination. As the branching fraction for Λ_{c}^{+}→Λe^{+}ν_{e} is the benchmark for those of other Λ_{c}^{+} semileptonic channels, our result provides a unique test of different theoretical models, which is the most stringent to date.

摘要

我们报告了对Λc+→Λe+νe绝对分支比的首次测量。该测量基于在质心能量√s = 4.599 GeV下产生的567 pb−1的e+e−湮灭数据，此能量刚好高于Λc+Λc−阈值。数据是利用北京谱仪III（BESIII）探测器在BEPCII储存环上收集的。确定分支比为B(Λc+→Λe+νe)=[3.63±0.38(统计)±0.20(系统)]%，与当前的间接测定相比，精度有显著提高。由于Λc+→Λe+νe的分支比是其他Λc+半轻子衰变道分支比的基准，我们的结果为不同理论模型提供了独特的检验，这是迄今为止最严格的检验。