Measurements of the branching fractions of the semileptonic decays $Ξ_{c}^{0} \to Ξ^{-} \ell^{+} ν_{\ell}$ and the asymmetry parameter of $Ξ_{c}^{0} \to Ξ^{-} π^{+}$
Creators: name: Belle Collaboration
name: Li, Y. B.
name: Shen, C. P.
name: Adachi, I.
name: Adamczyk, K.
name: Aihara, H.
name: Said, S. Al
name: Asner, D. M.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Behera, P.
name: Bennett, J.
name: Bessner, M.
name: Bhardwaj, V.
name: Bhuyan, B.
name: Bilka, T.
name: Biswal, J.
name: Bonvicini, G.
name: Bozek, A.
name: Bračko, M.
name: Browder, T. E.
name: Campajola, M.
name: Červenkov, D.
name: Chang, M. -C.
name: Chen, A.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, K.
name: Cho, S. -J.
name: Choi, S. -K.
name: Choi, Y.
name: Choudhury, S.
name: Cinabro, D.
name: Cunliffe, S.
name: Das, S.
name: Dash, N.
name: De Nardo, G.
name: Dhamija, R.
name: Di Capua, F.
name: Dong, T. V.
name: Eidelman, S.
name: Epifanov, D.
name: Ferber, T.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Giri, A.
name: Goldenzweig, P.
name: Grzymkowska, O.
name: Gudkova, K.
name: Hadjivasiliou, C.
name: Hartbrich, O.
name: Hayasaka, K.
name: Hayashii, H.
name: Villanueva, M. Hernandez
name: Hsu, C. -L.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Jacobs, W. W.
name: Jia, S.
name: Jin, Y.
name: Joo, C. W.
name: Joo, K. K.
name: Kang, K. H.
name: Karyan, G.
name: Kato, Y.
name: Kichimi, H.
name: Kim, C. H.
name: Kim, D. Y.
name: Kim, K. -H.
name: Kim, S. H.
name: Kinoshita, K.
name: Kodyš, P.
name: Konno, T.
name: Korobov, A.
name: Korpar, S.
name: Kovalenko, E.
name: Križan, P.
name: Kroeger, R.
name: Krokovny, P.
name: Kuhr, T.
name: Kumar, M.
name: Kumar, R.
name: Kumara, K.
name: Kuzmin, A.
name: Kwon, Y. -J.
name: Lalwani, K.
name: Lange, J. S.
name: Lee, I. S.
name: Lee, S. C.
name: Li, C. H.
name: Li, L. K.
name: Gioi, L. Li
name: Libby, J.
name: Lieret, K.
name: Liventsev, D.
name: Masuda, M.
name: Matvienko, D.
name: McNeil, J. T.
name: Metzner, F.
name: Mizuk, R.
name: Mohanty, G. B.
name: Moon, T. J.
name: Mori, T.
name: Mussa, R.
name: Natochii, A.
name: Nayak, L.
name: Nayak, M.
name: Niiyama, M.
name: Nisar, N. K.
name: Nishida, S.
name: Nishimura, K.
name: Ogawa, S.
name: Ono, H.
name: Onuki, Y.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pang, T.
name: Pardi, S.
name: Park, H.
name: Patra, S.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Podobnik, T.
name: Popov, V.
name: Prencipe, E.
name: Prim, M. T.
name: Röhrken, M.
name: Rostomyan, A.
name: Rout, N.
name: Russo, G.
name: Sahoo, D.
name: Sakai, Y.
name: Sandilya, S.
name: Santelj, L.
name: Sanuki, T.
name: Savinov, V.
name: Schnell, G.
name: Schwanda, C.
name: Seino, Y.
name: Senyo, K.
name: Shapkin, M.
name: Sharma, C.
name: Shiu, J. -G.
name: Sokolov, A.
name: Solovieva, E.
name: Starič, M.
name: Stottler, Z. S.
name: Sumihama, M.
name: Tamponi, U.
name: Tanida, K.
name: Tenchini, F.
name: Uchida, M.
name: Uehara, S.
name: Uglov, T.
name: Uno, K.
name: Uno, S.
name: Usov, Y.
name: Van Tonder, R.
name: Varner, G.
name: Vinokurova, A.
name: Vossen, A.
name: Wang, C. H.
name: Wang, M. -Z.
name: Wang, P.
name: Wang, X. L.
name: Watanabe, M.
name: Watanuki, S.
name: Won, E.
name: Xu, X.
name: Yan, W.
name: Yang, S. B.
name: Ye, H.
name: Yin, J. H.
name: Yuan, C. Z.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Using data samples of 89.5 and 711 fb$^{-1}$ recorded at energies of $\sqrt{s}=10.52$ and $10.58$ GeV, respectively, with the Belle detector at the KEKB $e^+e^-$ collider, we report measurements of branching fractions of semileptonic decays $Ξ_{c}^{0} \to Ξ^{-} \ell^{+} ν_{\ell}$ ($\ell=e$ or $μ$) and the $CP$-asymmetry parameter of $Ξ_{c}^{0} \to Ξ^{-} π^{+}$ decay. The branching fractions are measured to be ${\cal B}(Ξ_{c}^{0} \to Ξ^{-} e^{+} ν_{e})=(1.31 \pm 0.04 \pm 0.07 \pm 0.38)\%$ and ${\cal B}(Ξ_{c}^{0} \to Ξ^{-} μ^{+} ν_μ)=(1.27 \pm 0.06 \pm 0.10 \pm 0.37)\%$, and the decay parameter $α_{Ξπ}$ is measured to be $0.63 \pm 0.03 \pm 0.01$ with much improved precision compared to the current world average. The corresponding ratio ${\cal B}(Ξ_{c}^{0} \to Ξ^{-} e^{+} ν_{e})/{\cal B}(Ξ_{c}^{0} \to Ξ^{-} μ^{+} ν_μ)$ is $1.03 \pm 0.05\pm 0.07$, which is consistent with the expectation of lepton flavor universality. The first measured asymmetry parameter ${\cal A}_{CP} = (α_{Ξ^{-}π^{+}} + α_{\barΞ^{+}π^{-}})/(α_{Ξ^{-}π^{+}} - α_{\barΞ^{+}π^{-}}) = 0.024 \pm 0.052 \pm 0.014$ is found to be consistent with zero. The first and the second uncertainties above are statistical and systematic, respectively, while the third ones arise due to the uncertainty of the $Ξ_{c}^{0} \to Ξ^{-} π^+$ branching fraction.
description: 8 pages, 2 figures, 1 table, accepted for publication as a Letter in Physical Review Letters