Λ→pμ⁻ν̅ₘ的绝对分支比的首次测量。

First Measurement of the Absolute Branching Fraction of Λ→pμ^{-}ν[over ¯]_{μ}.

作者信息

Ablikim M, Achasov M N, Adlarson P, Ahmed S, Albrecht M, Aliberti R, Amoroso A, An M R, An Q, Bai X H, Bai Y, Bakina O, Baldini Ferroli R, Balossino I, Ban Y, Begzsuren K, Berger N, Bertani M, Bettoni D, Bianchi F, Bloms J, Bortone A, Boyko I, Briere R A, Cai H, Cai X, Calcaterra A, Cao G F, Cao N, Cetin S A, Chang J F, Chang W L, Chelkov G, Chen D Y, Chen G, Chen H S, Chen M L, Chen S J, Chen X R, Chen Y B, Chen Z J, Cheng W S, Cibinetto G, Cossio F, Cui X F, Dai H L, Dai J P, Dai X C, Dbeyssi A, de Boer R E, 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, Dong X, Du S X, Fan Y L, Fang J, Fang S S, Fang Y, Farinelli R, Fava L, Feldbauer F, Felici G, Feng C Q, Feng J H, Fritsch M, Fu C D, Gao Y, Gao Y, Gao Y, Gao Y G, Garzia I, Ge P T, Geng C, Gersabeck E M, Gilman A, Goetzen K, Gong L, Gong W X, Gradl W, Greco M, Gu L M, Gu M H, Gu Y T, Guan C Y, Guo A Q, Guo L B, Guo R P, Guo Y P, Guskov A, Han T T, Han W Y, Hao X Q, Harris F A, He K L, Heinsius F H, Heinz C H, Heng Y K, Herold C, Himmelreich M, Holtmann T, Hou G Y, Hou Y R, Hou Z L, Hu H M, Hu J F, Hu T, Hu Y, Huang G S, Huang L Q, Huang X T, Huang Y P, Huang Z, Hussain T, Hüsken N, Ikegami Andersson W, Imoehl W, Irshad M, Jaeger S, Janchiv S, Ji Q, Ji Q P, Ji X B, Ji X L, Ji Y Y, Jiang H B, Jiang X S, Jiao J B, Jiao Z, Jin S, Jin Y, Jing M Q, Johansson T, Kalantar-Nayestanaki N, Kang X S, Kappert R, Kavatsyuk M, Ke B C, Keshk I K, Khoukaz A, Kiese P, Kiuchi R, Kliemt R, Koch L, Kolcu O B, Kopf B, Kuemmel M, Kuessner M, Kupsc A, Kurth M G, Kühn W, Lane J J, Lange J S, Larin P, Lavania A, Lavezzi L, Lei Z H, Leithoff H, Lellmann M, Lenz T, Li C, Li C H, Li Cheng, Li D M, Li F, Li G, Li H, Li H, Li H B, Li H J, Li J L, Li J Q, Li J S, Li Ke, Li L K, Li Lei, Li P R, Li S Y, Li W D, Li W G, Li X H, Li X L, Li Xiaoyu, Li Z Y, Liang H, Liang H, Liang H, Liang Y F, Liang Y T, Liao G R, Liao L Z, Libby J, Limphirat A, Lin C X, Lin T, Liu B J, Liu C X, Liu D, Liu F H, Liu Fang, Liu Feng, Liu H B, Liu H M, Liu Huanhuan, Liu Huihui, Liu J B, Liu J L, Liu J Y, Liu K, Liu K Y, Liu Ke, Liu L, Liu M H, Liu P L, Liu Q, Liu Q, Liu S B, Liu Shuai, Liu T, Liu T, Liu W M, Liu X, Liu Y, Liu Y B, Liu Z A, Liu Z Q, Lou X C, Lu F X, Lu H J, Lu J D, Lu J G, Lu X L, Lu Y, Lu Y P, Luo C L, Luo M X, Luo P W, Luo T, Luo X L, Lyu X R, Ma F C, Ma H L, Ma L L, Ma M M, Ma Q M, Ma R Q, Ma R T, Ma X X, Ma X Y, Maas F E, Maggiora M, Maldaner S, Malde S, Malik Q A, Mangoni A, Mao Y J, Mao Z P, Marcello S, Meng Z X, Messchendorp J G, Mezzadri G, Min T J, Mitchell R E, Mo X H, Muchnoi N Yu, Muramatsu H, Nakhoul S, Nefedov Y, Nerling F, Nikolaev I B, Ning Z, Nisar S, Olsen S L, Ouyang Q, Pacetti S, Pan X, Pan Y, Pathak A, Pathak A, Patteri P, Pelizaeus M, Peng H P, Peters K, Pettersson J, Ping J L, Ping R G, Pogodin S, Poling R, Prasad V, Qi H, Qi H R, Qi K H, Qi M, Qi T Y, Qian S, Qian W B, Qian Z, Qiao C F, Qin L Q, Qin X P, Qin X S, Qin Z H, Qiu J F, Qu S Q, Rashid K H, Ravindran K, Redmer C F, Rivetti A, Rodin V, Rolo M, Rong G, Rosner Ch, Rump M, Sang H S, Sarantsev A, Schelhaas Y, Schnier C, Schoenning K, Scodeggio M, Shan D C, Shan W, Shan X Y, Shangguan J F, Shao M, Shen C P, Shen H F, Shen P X, Shen X Y, Shi H C, Shi R S, Shi X, Shi X D, Song J J, Song W M, Song Y X, Sosio S, Spataro S, Su K X, Su P P, Sui F F, Sun G X, Sun H K, Sun J F, Sun L, Sun S S, Sun T, Sun W Y, Sun W Y, Sun X, Sun Y J, Sun Y Z, Sun Z T, Tan Y H, Tan Y X, Tang C J, Tang G Y, Tang J, Teng J X, Thoren V, Tian W H, Tian Y T, Uman I, Wang B, Wang C W, Wang D Y, Wang H J, Wang H P, Wang K, Wang L L, Wang M, Wang M Z, Wang Meng, Wang S, Wang W, Wang W H, Wang W P, Wang X, Wang X F, Wang X L, Wang Y, Wang Y, Wang Y D, Wang Y F, Wang Y Q, Wang Y Y, Wang Z, Wang Z Y, Wang Ziyi, Wang Zongyuan, Wei D H, Weidner F, Wen S P, White D J, Wiedner U, Wilkinson G, Wolke M, Wollenberg L, Wu J F, Wu L H, Wu L J, Wu X, Wu Z, Xia L, Xiao H, Xiao S Y, Xiao Z J, Xie X H, Xie Y G, Xie Y H, Xing T Y, Xu C J, Xu G F, Xu Q J, Xu W, Xu X P, Xu Y C, Yan F, Yan L, Yan W B, Yan W C, Yan Xu, Yang H J, Yang H X, Yang L, Yang S L, Yang Y X, Yang Yifan, Yang Zhi, Ye M, Ye M H, Yin J H, You Z Y, Yu B X, Yu C X, Yu G, Yu J S, Yu T, Yuan C Z, Yuan L, Yuan X Q, Yuan Y, Yuan Z Y, Yue C X, Zafar A A, Zeng X Zeng, Zeng Y, Zhang A Q, Zhang B X, Zhang Guangyi, Zhang H, Zhang H H, Zhang H H, Zhang H Y, Zhang J L, Zhang J Q, Zhang J W, Zhang J Y, Zhang J Z, Zhang Jianyu, Zhang Jiawei, Zhang L M, Zhang L Q, Zhang Lei, Zhang S, Zhang S F, Zhang Shulei, Zhang X D, Zhang X Y, Zhang Y, Zhang Y T, Zhang Y H, Zhang Yan, Zhang Yao, Zhang Z Y, Zhao G, Zhao J, Zhao J Y, Zhao J Z, Zhao Lei, Zhao Ling, Zhao M G, Zhao Q, Zhao S J, Zhao Y B, Zhao Y X, Zhao Z G, Zhemchugov A, Zheng B, Zheng J P, Zheng Y H, Zhong B, Zhong C, Zhou L P, Zhou Q, Zhou X, Zhou X K, Zhou X R, Zhou X Y, Zhu A N, Zhu J, Zhu K, Zhu K J, Zhu S H, Zhu T J, Zhu W J, Zhu W J, Zhu Y C, Zhu Z A, 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. 2021 Sep 17;127(12):121802. doi: 10.1103/PhysRevLett.127.121802.

DOI:10.1103/PhysRevLett.127.121802

PMID:34597097

Abstract

The absolute branching fraction of Λ→pμ^{-}ν[over ¯]{μ} is reported for the first time based on an e^{+}e^{-} annihilation sample of 10×10^{9} J/ψ events collected with the BESIII detector at sqrt[s]=3.097 GeV. The branching fraction is determined to be B(Λ→pμ^{-}ν[over ¯]{μ})=[1.48±0.21(stat)±0.08(syst)]×10^{-4}, which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Λ→pe^{-}ν[over ¯]{e}), we obtain the ratio {[Γ(Λ→pμ^{-}ν[over ¯]{μ})]/[Γ(Λ→pe^{-}ν[over ¯]{e})]} to be 0.178±0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Λ→pμ^{-}ν[over ¯]{μ} and Λ[over ¯]→p[over ¯]μ^{+}ν_{μ} is also determined, and no evidence for CP violation is found.

摘要

基于在北京谱仪III（BESIII）探测器上于质心能量(\sqrt{s}=3.097) GeV收集的(10×10^{9})个(J/\psi)事例的(e^{+}e^{-})湮灭样本，首次报道了(\Lambda→p\mu^{-}\overline{\nu}{\mu})的绝对分支比。测得分支比为(B(\Lambda→p\mu^{-}\overline{\nu}{\mu}) = [1.48±0.21(统计)±0.08(系统)]×10^{-4})，与之前的间接测量相比，精度提高了约30%。将此结果与(B(\Lambda→pe^{-}\overline{\nu}{e}))的世界平均值相结合，我们得到(\frac{\Gamma(\Lambda→p\mu^{-}\overline{\nu}{\mu})}{\Gamma(\Lambda→pe^{-}\overline{\nu}{e})})的比值为(0.178±0.028)，这与假设轻子味普适性的标准模型预测相符。还确定了(\Lambda→p\mu^{-}\overline{\nu}{\mu})和(\overline{\Lambda}→\overline{p}\mu^{+}\nu_{\mu})分支比的不对称性，未发现CP破坏的证据。