학술논문

A new graph-neural-network flavor tagger for Belle II and measurement of $\sin2\phi_1$ in $B^0 \to J/\psi K^0_\text{S}$ decays
Document Type
Working Paper
Author
Belle II CollaborationAdachi, I.Aggarwal, L.Ahmed, H.Aihara, H.Akopov, N.Aloisio, A.Ky, N. AnhAsner, D. M.Atmacan, H.Aushev, T.Aushev, V.Aversano, M.Ayad, R.Babu, V.Bae, H.Bahinipati, S.Bambade, P.Banerjee, Sw.Bansal, S.Barrett, M.Baudot, J.Baur, A.Beaubien, A.Becherer, F.Becker, J.Bennett, J. V.Bernlochner, F. U.Bertacchi, V.Bertemes, M.Bertholet, E.Bessner, M.Bettarini, S.Bhuyan, B.Bianchi, F.Bierwirth, L.Bilka, T.Bilokin, S.Biswas, D.Bobrov, A.Bodrov, D.Bolz, A.Bondar, A.Bozek, A.Bračko, M.Branchini, P.Briere, R. A.Browder, T. E.Budano, A.Bussino, S.Campajola, M.Cao, L.Casarosa, G.Cecchi, C.Cerasoli, J.Chang, M. -C.Chang, P.Cheema, P.Chen, C.Cheon, B. G.Chilikin, K.Chirapatpimol, K.Cho, H. -E.Cho, K.Cho, S. -J.Choi, S. -K.Choudhury, S.Cochran, J.Corona, L.Das, S.Dattola, F.De La Cruz-Burelo, E.De La Motte, S. A.De Nardo, G.De Nuccio, M.De Pietro, G.de Sangro, R.Destefanis, M.Dey, S.Dhamija, R.Di Canto, A.Di Capua, F.Doležal, Z.Dong, T. V.Dorigo, M.Dort, K.Dossett, D.Dreyer, S.Dubey, S.Dujany, G.Ecker, P.Eliachevitch, M.Feichtinger, P.Ferber, T.Ferlewicz, D.Fillinger, T.Finck, C.Finocchiaro, G.Fodor, A.Forti, F.Frey, A.Fulsom, B. G.Gabrielli, A.Ganiev, E.Garcia-Hernandez, M.Garg, R.Gaudino, G.Gaur, V.Gaz, A.Gellrich, A.Ghevondyan, G.Ghosh, D.Ghumaryan, H.Giakoustidis, G.Giordano, R.Giri, A.Glazov, A.Gobbo, B.Godang, R.Gogota, O.Goldenzweig, P.Gradl, W.Grammatico, T.Graziani, E.Greenwald, D.Gruberová, Z.Gu, T.Guan, Y.Gudkova, K.Han, Y.Hara, K.Hara, T.Hayasaka, K.Hayashii, H.Hazra, S.Hearty, C.Hedges, M. T.Heidelbach, A.de la Cruz, I. HerediaVillanueva, M. HernándezHiguchi, T.Hoek, M.Hohmann, M.Horak, P.Hsu, C. -L.Humair, T.Iijima, T.Inami, K.Ipsita, N.Ishikawa, A.Itoh, R.Iwasaki, M.Jackson, P.Jacobs, W. W.Jaffe, D. E.Jang, E. -J.Ji, Q. P.Jia, S.Jin, Y.Joo, K. K.Junkerkalefeld, H.Kakuno, H.Kalita, D.Kaliyar, A. B.Kandra, J.Kang, K. H.Kang, S.Karyan, G.Kawasaki, T.Keil, F.Kiesling, C.Kim, C. -H.Kim, D. Y.Kim, K. -H.Kim, Y. -K.Kindo, H.Kinoshita, K.Kodyš, P.Koga, T.Kohani, S.Kojima, K.Korobov, A.Korpar, S.Kovalenko, E.Kowalewski, R.Kraetzschmar, T. M. G.Križan, P.Krokovny, P.Kuhr, T.Kulii, Y.Kumar, J.Kumar, M.Kumar, R.Kumara, K.Kunigo, T.Kuzmin, A.Kwon, Y. -J.Lacaprara, S.Lai, Y. -T.Lam, T.Lanceri, L.Lange, J. S.Laurenza, M.Leboucher, R.Diberder, F. R. LeLee, M. J.Levit, D.Li, C.Li, L. K.Li, Y.Li, Y. B.Libby, J.Lin, Y. -R.Liu, M. H.Liu, Q. Y.Liu, Z. Q.Liventsev, D.Longo, S.Lueck, T.Lyu, C.Ma, Y.Maggiora, M.Maharana, S. P.Maiti, R.Maity, S.Mancinelli, G.Manfredi, R.Manoni, E.Mantovano, M.Marcantonio, D.Marcello, S.Marinas, C.Martel, L.Martellini, C.Martini, A.Martinov, T.Massaccesi, L.Masuda, M.Matsuoka, K.Matvienko, D.Maurya, S. K.McKenna, J. A.Mehta, R.Meier, F.Merola, M.Metzner, F.Miller, C.Mirra, M.Mitra, S.Miyabayashi, K.Miyake, H.Mizuk, R.Mohanty, G. B.Molina-Gonzalez, N.Mondal, S.Moneta, S.Moser, H. -G.Mrvar, M.Mussa, R.Nakamura, I.Nakamura, K. R.Nakao, M.Nakazawa, Y.Charan, A. NarimaniNaruki, M.Narwal, D.Natkaniec, Z.Natochii, A.Nayak, L.Nayak, M.Nazaryan, G.Neu, M.Niebuhr, C.Nishida, S.Ogawa, S.Onishchuk, Y.Ono, H.Onuki, Y.Oskin, P.Otani, F.Pakhlov, P.Pakhlova, G.Panta, A.Pardi, S.Parham, K.Park, H.Park, S. -H.Paschen, B.Passeri, A.Patra, S.Paul, S.Pedlar, T. K.Peschke, R.Pestotnik, R.Piccolo, M.Piilonen, L. E.Angioni, G. PinnaPodesta-Lerma, P. L. M.Podobnik, T.Pokharel, S.Praz, C.Prell, S.Prencipe, E.Prim, M. T.Purwar, H.Rados, P.Raeuber, G.Raiz, S.Rauls, N.Reif, M.Reiter, S.Remnev, M.Ripp-Baudot, I.Rizzo, G.Roehrken, M.Roney, J. M.Rostomyan, A.Rout, N.Russo, G.Sanders, D. A.Sandilya, S.Sangal, A.Santelj, L.Sato, Y.Savinov, V.Scavino, B.Schmitt, C.Schwanda, C.Schwickardi, M.Seino, Y.Selce, A.Senyo, K.Serrano, J.Sevior, M. E.Sfienti, C.Shan, W.Shi, X. D.Shillington, T.Shimasaki, T.Shiu, J. -G.Shtol, D.Sibidanov, A.Simon, F.Singh, J. B.Skorupa, J.Sobie, R. J.Sobotzik, M.Soffer, A.Sokolov, A.Solovieva, E.Spataro, S.Spruck, B.Starič, M.Stavroulakis, P.Stefkova, S.Stroili, R.Sumihama, M.Sumisawa, K.Sutcliffe, W.Svidras, H.Takizawa, M.Tamponi, U.Tanaka, S.Tanida, K.Tenchini, F.Tittel, O.Tiwary, R.Tonelli, D.Torassa, E.Trabelsi, K.Tsaklidis, I.Uchida, M.Ueda, I.Uematsu, Y.Unger, K.Unno, Y.Uno, K.Uno, S.Urquijo, P.Ushiroda, Y.Vahsen, S. E.van Tonder, R.Varvell, K. E.Veronesi, M.Vinokurova, A.Vismaya, V. S.Vitale, L.Vobbilisetti, V.Volpe, R.Wach, B.Wakai, M.Wallner, S.Wang, E.Wang, M. -Z.Wang, X. L.Wang, Z.Warburton, A.Watanuki, S.Wessel, C.Won, E.Xu, X. P.Yabsley, B. D.Yamada, S.Yan, W.Yang, S. B.Yelton, J.Yin, J. H.Yoshihara, K.Yuan, C. Z.Yusa, Y.Zhang, B.Zhilich, V.Zhou, Q. D.Zhou, X. Y.Zhukova, V. I.Žlebčík, R.
Source
Subject
High Energy Physics - Experiment
Language
Abstract
We present GFlaT, a new algorithm that uses a graph-neural-network to determine the flavor of neutral $B$ mesons produced in $\Upsilon(4S)$ decays. It improves previous algorithms by using the information from all charged final-state particles and the relations between them. We evaluate its performance using $B$ decays to flavor-specific hadronic final states reconstructed in a 362 $\text{fb}^{-1}$ sample of electron-positron collisions collected at the $\Upsilon(4S)$ resonance with the Belle II detector at the SuperKEKB collider. We achieve an effective tagging efficiency of $(37.40 \pm 0.43 \pm 0.36) \%$, where the first uncertainty is statistical and the second systematic, which is $18\%$ better than the previous Belle II algorithm. Demonstrating the algorithm, we use $B^{0}\to J/\psi K^0_\text{S}$ decays to measure the mixing-induced and direct $CP$ violation parameters, $S = (0.724 \pm 0.035 \pm 0.014)$ and $C = (-0.035 \pm 0.026 \pm 0.013)$.
Comment: 15 pages, 9 figures