$B$-flavor tagging at Belle II
Creators: name: Abudinén, F.
name: Akopov, N.
name: Aloisio, A.
name: Babu, V.
name: Banerjee, Sw.
name: Bauer, M.
name: Bennett, J. V.
name: Bernlochner, F. U.
name: Bessner, M.
name: Bettarini, S.
name: Bilka, T.
name: Bilokin, S.
name: Biswas, D.
name: Bodrov, D.
name: Borah, J.
name: Bračko, M.
name: Branchini, P.
name: Budano, A.
name: Campajola, M.
name: Casarosa, G.
name: Cecchi, C.
name: Cheaib, R.
name: Chekelian, V.
name: Chen, C.
name: Chen, Y. Q.
name: Cho, H. -E.
name: Cunliffe, S.
name: De Nardo, G.
name: De Pietro, G.
name: de Sangro, R.
name: Dey, S.
name: Di Canto, A.
name: Di Capua, F.
name: Dong, T. V.
name: Dujany, G.
name: Ecker, P.
name: Eliachevitch, M.
name: Ferber, T.
name: Forti, F.
name: Ganiev, E.
name: Gaz, A.
name: Gelb, M.
name: Gemmler, J.
name: Godang, R.
name: Goldenzweig, P.
name: Graziani, E.
name: Hara, K.
name: Hershenhorn, A.
name: Higuchi, T.
name: Hill, E. C.
name: Hohmann, M.
name: Humair, T.
name: Inguglia, G.
name: Junkerkalefeld, H.
name: Karl, R.
name: Kato, Y.
name: Keck, T.
name: Kiesling, C.
name: Kim, C. -H.
name: Kohani, S.
name: Komarov, I.
name: Kraetzschmar, T. M. G.
name: Križan, P.
name: Krohn, J. F.
name: Kuhr, T.
name: Kumar, J.
name: Kumara, K.
name: Kurz, S.
name: Lacaprara, S.
name: La Licata, C.
name: Laurenza, M.
name: Lautenbach, K.
name: Lee, S. C.
name: Lieret, K.
name: Gioi, L. Li
name: Liu, Q. Y.
name: Longo, S.
name: Maggiora, M.
name: Manoni, E.
name: Marinas, C.
name: Martini, A.
name: Meier, F.
name: Merola, M.
name: Metzner, F.
name: Milesi, M.
name: Miyabayashi, K.
name: Mohanty, G. B.
name: Mueller, F.
name: Murphy, C.
name: Oxford, E. R.
name: Park, S. -H.
name: Passeri, A.
name: Pham, F.
name: Piilonen, L. E.
name: Pokharel, S.
name: Prim, M. T.
name: Pulvermacher, C.
name: Rados, P.
name: Ritter, M.
name: Rostomyan, A.
name: Sandilya, S.
name: Santelj, L.
name: Sato, Y.
name: Schwartz, A. J.
name: Sevior, M. E.
name: Soffer, A.
name: Spataro, S.
name: Stroili, R.
name: Sutcliffe, W.
name: Tagnani, D.
name: Takizawa, M.
name: Tamponi, U.
name: Tenchini, F.
name: Torassa, E.
name: Urquijo, P.
name: Vitale, L.
name: Yusa, Y.
name: Zani, L.
name: Zhou, Q. D.
name: Žlebčík, R.
name: Zupanc, A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report on new flavor tagging algorithms developed to determine the quark-flavor content of bottom ($B$) mesons at Belle II. The algorithms provide essential inputs for measurements of quark-flavor mixing and charge-parity violation. We validate and evaluate the performance of the algorithms using hadronic $B$ decays with flavor-specific final states reconstructed in a data set corresponding to an integrated luminosity of $62.8$ fb$^{-1}$, collected at the $Υ$(4$S$) resonance with the Belle II detector at the SuperKEKB collider. We measure the total effective tagging efficiency to be $\varepsilon_{\rm eff} = \big(30.0 \pm 1.2(\text{stat}) \pm 0.4(\text{syst})\big)\%$ for a category-based algorithm and $\varepsilon_{\rm eff} = \big(28.8 \pm 1.2(\text{stat}) \pm 0.4(\text{syst})\big)\%$ for a deep-learning-based algorithm.