Precise Measurements of Decay Parameters and $CP$ Asymmetry with Entangled $Λ-\barΛ$ Pairs
Creators: name: BESIII Collaboration
name: Ablikim, M.
name: Achasov, M. N.
name: Adlarson, P.
name: Albrecht, M.
name: Aliberti, R.
name: Amoroso, A.
name: An, M. R.
name: An, Q.
name: Bai, X. H.
name: Bai, Y.
name: Bakina, O.
name: Ferroli, R. Baldini
name: Balossino, I.
name: Ban, Y.
name: Batozskaya, V.
name: Becker, D.
name: Begzsuren, K.
name: Berger, N.
name: Bertani, M.
name: Bettoni, D.
name: Bianchi, F.
name: Bloms, J.
name: Bortone, A.
name: Boyko, I.
name: Briere, R. A.
name: Brueggemann, A.
name: Cai, H.
name: Cai, X.
name: Calcaterra, A.
name: Cao, G. F.
name: Cao, N.
name: Cetin, S. A.
name: Chang, J. F.
name: Chang, W. L.
name: Chelkov, G.
name: Chen, C.
name: Chen, Chao
name: Chen, G.
name: Chen, H. S.
name: Chen, M. L.
name: Chen, S. J.
name: Chen, S. M.
name: Chen, T.
name: Chen, X. R.
name: Chen, X. T.
name: Chen, Y. B.
name: Chen, Z. J.
name: Cheng, W. S.
name: Choi, S. K.
name: Chu, X.
name: Cibinetto, G.
name: Cossio, F.
name: Cui, J. J.
name: Dai, H. L.
name: Dai, J. P.
name: Dbeyssi, A.
name: de Boer, R. E.
name: Dedovich, D.
name: Deng, Z. Y.
name: Denig, A.
name: Denysenko, I.
name: Destefanis, M.
name: De Mori, F.
name: Ding, Y.
name: Dong, J.
name: Dong, L. Y.
name: Dong, M. Y.
name: Dong, X.
name: Du, S. X.
name: Egorov, P.
name: Fan, Y. L.
name: Fang, J.
name: Fang, S. S.
name: Fang, W. X.
name: Fang, Y.
name: Farinelli, R.
name: Fava, L.
name: Feldbauer, F.
name: Felici, G.
name: Feng, C. Q.
name: Feng, J. H.
name: Fischer, K
name: Fritsch, M.
name: Fritzsch, C.
name: Fu, C. D.
name: Gao, H.
name: Gao, Y. N.
name: Gao, Yang
name: Garbolino, S.
name: Garzia, I.
name: Ge, P. T.
name: Ge, Z. W.
name: Geng, C.
name: Gersabeck, E. M.
name: Gilman, A
name: Goetzen, K.
name: Gong, L.
name: Gong, W. X.
name: Gradl, W.
name: Greco, M.
name: Gu, L. M.
name: Gu, M. H.
name: Gu, Y. T.
name: Guan, C. Y
name: Guo, A. Q.
name: Guo, L. B.
name: Guo, R. P.
name: Guo, Y. P.
name: Guskov, A.
name: Han, T. T.
name: Han, W. Y.
name: Hao, X. Q.
name: Harris, F. A.
name: He, K. K.
name: He, K. L.
name: Heinsius, F. H.
name: Heinz, C. H.
name: Heng, Y. K.
name: Herold, C.
name: Himmelreich, M.
name: Hou, G. Y.
name: Hou, Y. R.
name: Hou, Z. L.
name: Hu, H. M.
name: Hu, J. F.
name: Hu, T.
name: Hu, Y.
name: Huang, G. S.
name: Huang, K. X.
name: Huang, L. Q.
name: Huang, L. Q.
name: Huang, X. T.
name: Huang, Y. P.
name: Huang, Z.
name: Hussain, T.
name: Hüsken, N
name: Imoehl, W.
name: Irshad, M.
name: Jackson, J.
name: Jaeger, S.
name: Janchiv, S.
name: Jang, E.
name: Jeong, J. H.
name: Ji, Q.
name: Ji, Q. P.
name: Ji, X. B.
name: Ji, X. L.
name: Ji, Y. Y.
name: Jia, Z. K.
name: Jiang, H. B.
name: Jiang, S. S.
name: Jiang, X. S.
name: Jiang, Y.
name: Jiao, J. B.
name: Jiao, Z.
name: Jin, S.
name: Jin, Y.
name: Jing, M. Q.
name: Johansson, T.
name: Kalantar-Nayestanaki, N.
name: Kang, X. S.
name: Kappert, R.
name: Ke, B. C.
name: Keshk, I. K.
name: Khoukaz, A.
name: Kiese, P.
name: Kiuchi, R.
name: Kliemt, R.
name: Koch, L.
name: Kolcu, O. B.
name: Kopf, B.
name: Kuemmel, M.
name: Kuessner, M.
name: Kupsc, A.
name: Kühn, W.
name: Lane, J. J.
name: Lange, J. S.
name: Larin, P.
name: Lavania, A.
name: Lavezzi, L.
name: Lei, Z. H.
name: Leithoff, H.
name: Lellmann, M.
name: Lenz, T.
name: Li, C.
name: Li, C.
name: Li, C. H.
name: Li, Cheng
name: Li, D. M.
name: Li, F.
name: Li, G.
name: Li, H.
name: Li, H.
name: Li, H. B.
name: Li, H. J.
name: Li, H. N.
name: Li, J. Q.
name: Li, J. S.
name: Li, J. W.
name: Li, Ke
name: Li, L. J
name: Li, L. K.
name: Li, Lei
name: Li, M. H.
name: Li, P. R.
name: Li, S. X.
name: Li, S. Y.
name: Li, T.
name: Li, W. D.
name: Li, W. G.
name: Li, X. H.
name: Li, X. L.
name: Li, Xiaoyu
name: Liang, H.
name: Liang, H.
name: Liang, H.
name: Liang, Y. F.
name: Liang, Y. T.
name: Liao, G. R.
name: Liao, L. Z.
name: Libby, J.
name: Limphirat, A.
name: Lin, C. X.
name: Lin, D. X.
name: Lin, T.
name: Liu, B. J.
name: Liu, C. X.
name: Liu, D.
name: Liu, F. H.
name: Liu, Fang
name: Liu, Feng
name: Liu, G. M.
name: Liu, H.
name: Liu, H. B.
name: Liu, H. M.
name: Liu, Huanhuan
name: Liu, Huihui
name: Liu, J. B.
name: Liu, J. L.
name: Liu, J. Y.
name: Liu, K.
name: Liu, K. Y.
name: Liu, Ke
name: Liu, L.
name: Liu, Lu
name: Liu, M. H.
name: Liu, P. L.
name: Liu, Q.
name: Liu, S. B.
name: Liu, T.
name: Liu, W. K.
name: Liu, W. M.
name: Liu, X.
name: Liu, Y.
name: Liu, Y. B.
name: Liu, Z. A.
name: Liu, Z. Q.
name: Lou, X. C.
name: Lu, F. X.
name: Lu, H. J.
name: Lu, J. G.
name: Lu, X. L.
name: Lu, Y.
name: Lu, Y. P.
name: Lu, Z. H.
name: Luo, C. L.
name: Luo, M. X.
name: Luo, T.
name: Luo, X. L.
name: Lyu, X. R.
name: Lyu, Y. F.
name: Ma, F. C.
name: Ma, H. L.
name: Ma, L. L.
name: Ma, M. M.
name: Ma, Q. M.
name: Ma, R. Q.
name: Ma, R. T.
name: Ma, X. Y.
name: Ma, Y.
name: Maas, F. E.
name: Maggiora, M.
name: Maldaner, S.
name: Malde, S.
name: Malik, Q. A.
name: Mangoni, A.
name: Mao, Y. J.
name: Mao, Z. P.
name: Marcello, S.
name: Meng, Z. X.
name: Messchendorp, J. G.
name: Mezzadri, G.
name: Miao, H.
name: Min, T. J.
name: Mitchell, R. E.
name: Mo, X. H.
name: Muchnoi, N. Yu.
name: Nefedov, Y.
name: Nerling, F.
name: Nikolaev, I. B.
name: Ning, Z.
name: Nisar, S.
name: Niu, Y.
name: Olsen, S. L.
name: Ouyang, Q.
name: Pacetti, S.
name: Pan, X.
name: Pan, Y.
name: Pathak, A.
name: Pelizaeus, M.
name: Peng, H. P.
name: Peters, K.
name: Ping, J. L.
name: Ping, R. G.
name: Plura, S.
name: Pogodin, S.
name: Prasad, V.
name: Qi, F. Z.
name: Qi, H.
name: Qi, H. R.
name: Qi, M.
name: Qi, T. Y.
name: Qian, S.
name: Qian, W. B.
name: Qian, Z.
name: Qiao, C. F.
name: Qin, J. J.
name: Qin, L. Q.
name: Qin, X. P.
name: Qin, X. S.
name: Qin, Z. H.
name: Qiu, J. F.
name: Qu, S. Q.
name: Rashid, K. H.
name: Redmer, C. F.
name: Ren, K. J.
name: Rivetti, A.
name: Rodin, V.
name: Rolo, M.
name: Rong, G.
name: Rosner, Ch.
name: Ruan, S. N.
name: Sang, H. S.
name: Sarantsev, A.
name: Schelhaas, Y.
name: Schnier, C.
name: Schönning, K.
name: Scodeggio, M.
name: Shan, K. Y.
name: Shan, W.
name: Shan, X. Y.
name: Shangguan, J. F.
name: Shao, L. G.
name: Shao, M.
name: Shen, C. P.
name: Shen, H. F.
name: Shen, X. Y.
name: Shi, B. A.
name: Shi, H. C.
name: Shi, J. Y.
name: Shi, Q. Q.
name: Shi, R. S.
name: Shi, X.
name: Shi, X. D
name: Song, J. J.
name: Song, W. M.
name: Song, Y. X.
name: Sosio, S.
name: Spataro, S.
name: Stieler, F.
name: Su, K. X.
name: Su, P. P.
name: Su, Y. J.
name: Sun, G. X.
name: Sun, H.
name: Sun, H. K.
name: Sun, J. F.
name: Sun, L.
name: Sun, S. S.
name: Sun, T.
name: Sun, W. Y.
name: Sun, X
name: Sun, Y. J.
name: Sun, Y. Z.
name: Sun, Z. T.
name: Tan, Y. H.
name: Tan, Y. X.
name: Tang, C. J.
name: Tang, G. Y.
name: Tang, J.
name: Tao, L. Y
name: Tao, Q. T.
name: Tat, M.
name: Teng, J. X.
name: Thoren, V.
name: Tian, W. H.
name: Tian, Y.
name: Uman, I.
name: Wang, B.
name: Wang, B. L.
name: Wang, C. W.
name: Wang, D. Y.
name: Wang, F.
name: Wang, H. J.
name: Wang, H. P.
name: Wang, K.
name: Wang, L. L.
name: Wang, M.
name: Wang, M. Z.
name: Wang, Meng
name: Wang, S.
name: Wang, S.
name: Wang, T.
name: Wang, T. J.
name: Wang, W.
name: Wang, W. H.
name: Wang, W. P.
name: Wang, X.
name: Wang, X. F.
name: Wang, X. L.
name: Wang, Y.
name: Wang, Y. D.
name: Wang, Y. F.
name: Wang, Y. H.
name: Wang, Y. Q.
name: Wang, Yaqian
name: Wang, Z.
name: Wang, Z. Y.
name: Wang, Ziyi
name: Wei, D. H.
name: Weidner, F.
name: Wen, S. P.
name: White, D. J.
name: Wiedner, U.
name: Wilkinson, G.
name: Wolke, M.
name: Wollenberg, L.
name: Wu, J. F.
name: Wu, L. H.
name: Wu, L. J.
name: Wu, X.
name: Wu, X. H.
name: Wu, Y.
name: Wu, Z.
name: Xia, L.
name: Xiang, T.
name: Xiao, D.
name: Xiao, G. Y.
name: Xiao, H.
name: Xiao, S. Y.
name: Xiao, Y. L.
name: Xiao, Z. J.
name: Xie, C.
name: Xie, X. H.
name: Xie, Y.
name: Xie, Y. G.
name: Xie, Y. H.
name: Xie, Z. P.
name: Xing, T. Y.
name: Xu, C. F.
name: Xu, C. J.
name: Xu, G. F.
name: Xu, H. Y.
name: Xu, Q. J.
name: Xu, X. P.
name: Xu, Y. C.
name: Xu, Z. P.
name: Yan, F.
name: Yan, L.
name: Yan, W. B.
name: Yan, W. C.
name: Yang, H. J.
name: Yang, H. L.
name: Yang, H. X.
name: Yang, L.
name: Yang, S. L.
name: Yang, Tao
name: Yang, Y. F.
name: Yang, Y. X.
name: Yang, Yifan
name: Ye, M.
name: Ye, M. H.
name: Yin, J. H.
name: You, Z. Y.
name: Yu, B. X.
name: Yu, C. X.
name: Yu, G.
name: Yu, T.
name: Yuan, C. Z.
name: Yuan, L.
name: Yuan, S. C.
name: Yuan, X. Q.
name: Yuan, Y.
name: Yuan, Z. Y.
name: Yue, C. X.
name: Zafar, A. A.
name: Zeng, F. R.
name: Zeng, X. Zeng
name: Zeng, Y.
name: Zhan, Y. H.
name: Zhang, A. Q.
name: Zhang, B. L.
name: Zhang, B. X.
name: Zhang, D. H.
name: Zhang, G. Y.
name: Zhang, H.
name: Zhang, H. H.
name: Zhang, H. H.
name: Zhang, H. Y.
name: Zhang, J. L.
name: Zhang, J. Q.
name: Zhang, J. W.
name: Zhang, J. X.
name: Zhang, J. Y.
name: Zhang, J. Z.
name: Zhang, Jianyu
name: Zhang, Jiawei
name: Zhang, L. M.
name: Zhang, L. Q.
name: Zhang, Lei
name: Zhang, P.
name: Zhang, Q. Y.
name: Zhang, Shuihan
name: Zhang, Shulei
name: Zhang, X. D.
name: Zhang, X. M.
name: Zhang, X. Y.
name: Zhang, X. Y.
name: Zhang, Y.
name: Zhang, Y. T.
name: Zhang, Y. H.
name: Zhang, Yan
name: Zhang, Yao
name: Zhang, Z. H.
name: Zhang, Z. Y.
name: Zhang, Z. Y.
name: Zhao, G.
name: Zhao, J.
name: Zhao, J. Y.
name: Zhao, J. Z.
name: Zhao, Lei
name: Zhao, Ling
name: Zhao, M. G.
name: Zhao, Q.
name: Zhao, S. J.
name: Zhao, Y. B.
name: Zhao, Y. X.
name: Zhao, Z. G.
name: Zhemchugov, A.
name: Zheng, B.
name: Zheng, J. P.
name: Zheng, Y. H.
name: Zhong, B.
name: Zhong, C.
name: Zhong, X.
name: Zhou, H.
name: Zhou, L. P.
name: Zhou, X.
name: Zhou, X. K.
name: Zhou, X. R.
name: Zhou, X. Y.
name: Zhou, Y. Z.
name: Zhu, J.
name: Zhu, K.
name: Zhu, K. J.
name: Zhu, L. X.
name: Zhu, S. H.
name: Zhu, S. Q.
name: Zhu, T. J.
name: Zhu, W. J.
name: Zhu, Y. C.
name: Zhu, Z. A.
name: Zou, B. S.
name: Zou, J. H.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Based on 10 billion $J/ψ$ events collected at the BESIII experiment, a search for $CP$ violation in $Λ$ decay is performed in the difference between $CP$-odd decay parameters $α_{-}$ for $Λ\rightarrow pπ^-$ and $α_{+}$ for $\barΛ\rightarrow \bar{p}π^+$ by using the process $e^+e^- \to J/ψ\rightarrow Λ\barΛ$. With a five-dimensional fit to the full angular distributions of the daughter baryon, the most precise values for the decay parameters are determined to be $α_{-} = 0.7519 \pm 0.0036 \pm 0.0024$ and $α_{+} = -0.7559 \pm 0.0036 \pm 0.0030$, respectively. The $Λ$ and $\barΛ$ averaged value of the decay parameter is extracted to be $α_{\rm{avg}} = 0.7542 \pm 0.0010 \pm 0.0024$ with unprecedented accuracy. The $CP$ asymmetry $A_{CP}=(α_{-}+α_{+})/(α_{-}-α_{+})$ is determined to be $-0.0025 \pm 0.0046 \pm 0.0012$, which is one of the most precise measurements in the baryon sector. The reported results for the decay parameter will play an important role in the studies of the polarizations and $CP$ violations for the strange, charmed and beauty baryons.