{"paper":{"title":"Observation of $\\Upsilon(2S)\\to\\gamma \\eta_{b}(1S)$ decay","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"A. Bondar, A. Bozek, A. Chen, A. Garmash, A. Giri, A. Ishikawa, A. Kuzmin, A. M. Bakich, A. Rabusov, A. Rostomyan, A. Sokolov, A. Vinokurova, A. Vossen, A. Zupanc, B. Bhuyan, Belle Collaboration: B. G. Fulsom, B. G. Cheon, B. Pal, B. Shwartz, B. Wang, C. Bele\\~no, C. H. Wang, C. Kiesling, C. P. Shen, C. Schwanda, C. Van Hulse, C. Z. Yuan, D. Cinabro, D. Epifanov, D. Joffe, D. Kotchetkov, D. Liventsev, D. M. Asner, D. Matvienko, D. \\v{C}ervenkov, D. Y. Kim, E. Guido, E. Prencipe, E. Solovieva, E. Widmann, E. Won, F. Simon, F. Tenchini, G. B. Mohanty, G. Bonvicini, G. Inguglia, G. Pakhlova, G. Russo, G. Schnell, G. Varner, H. Aihara, H. Atmacan, H. B. Jeon, H. Hayashii, H. J. Kim, H. Kichimi, H. K. Moon, H. Miyata, H. Ono, H. Park, H. Ye, I. Adachi, I. Badhrees, I. S. Lee, J. Biswal, J. B. Kim, J. B. Singh, J. Dingfelder, J. E. Fast, J. F. Strube, J.-G. Shiu, J. Haba, J. H. Yin, J. Libby, J. S. Lange, K. Chilikin, K. Cho, K. Hayasaka, K. Inami, K. J. Nath, K. Kinoshita, K. K. Joo, K. Miyabayashi, K. Senyo, K. Sumisawa, K. Tanida, K. T. Kim, L. Cao, L. E. Piilonen, L. K. Li, L. Li Gioi, L. Santelj, M. Berger, M. Bra\\v{c}ko, M. E. Sevior, M. Gelb, M. Iwasaki, M. Lubej, M. Masuda, M. Merola, M. Nakao, M. Nayak, M. Niiyama, M. Ritter, M. Salehi, M. Stari\\v{c}, M. Sumihama, M. Takizawa, M. Uchida, M. Watanabe, N. Dash, N. Gabyshev, N. K. Nisar, O. Schneider, P. Behera, P. Goldenzweig, P. Kody\\v{s}, P. Kri\\v{z}an, P. Krokovny, P. Pakhlov, P. Urquijo, P. Wang, R. Ayad, R. Garg, R. Itoh, R. Kroeger, R. Kulasiri, R. Mizuk, R. Mussa, R. Pestotnik, R. van Tonder, S. Al Said, S. Choudhury, S. C. Lee, S. Cunliffe, S. Di Carlo, S. Eidelman, S. E. Vahsen, S. Hirose, S. H. Kim, S. Jia, S.-K. Choi, S. Korpar, S. Nishida, S. Ogawa, S. Okuno, S. Pardi, S. Paul, S. Sandilya, S. Uno, S. Watanuki, T.-A. Shibata, T. Aushev, T. Bilka, T. E. Browder, T. Ferber, T. Iijima, T. Julius, T. Kawasaki, T. K. Pedlar, T. Kuhr, T. Luo, T. Matsuda, T. Mori, T. Nanut, T. Sanuki, T. Sumiyoshi, T. Uglov, T. V. Dong, U. Tamponi, V. Aulchenko, V. Babu, V. Bansal, V. Bhardwaj, V. Chekelian, V. Gaur, V. Popov, V. Savinov, V. Shebalin, V. Vorobyev, V. Zhukova, V. Zhulanov, W.-S. Hou, W. Sutcliffe, W. W. Jacobs, X. L. Wang, Y. B. Li, Y. Choi, Y. Iwasaki, Y. Jin, Y.-J. Kwon, Y. Sakai, Y. Seino, Y. Unno, Z. Dole\\v{z}al, Z. Dr\\'asal, Z. Natkaniec, Z. P. Zhang","submitted_at":"2018-07-03T14:23:52Z","abstract_excerpt":"We report the observation of $\\Upsilon(2S)\\to\\gamma\\eta_{b}(1S)$ decay based on analysis of the inclusive photon spectrum of $24.7$ fb$^{-1}$ of $e^+ e^-$ collisions at the $\\Upsilon(2S)$ center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We measure a branching fraction of $\\mathcal{B}(\\Upsilon(2S)\\to\\gamma\\eta_{b}(1S))=(6.1^{+0.6+0.9}_{-0.7-0.6})\\times 10^{-4}$, and derive an $\\eta_{b}(1S)$ mass of $9394.8^{+2.7+4.5}_{-3.1-2.7}$ MeV/$c^{2}$, where the uncertainties are statistical and systematic, respectively. The significance of our meas"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1807.01201","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}