Fulsom, B. G.Pedlar, T. K.Adachi, I.Aihara, H.Al Said, S.Asner, D. M.Atmacan, H.Aulchenko, V.Aushev, T.Ayad, R.Babu, V.Badhrees, I.Bakich, A. M.Bansal, V.Behera, P.Beleno, C.Berger, M.Bhardwaj, V.Bhuyan, B.Bilka, T.Biswal, J.Bondar, A.Bonvicini, G.Bozek, A.Bracko, M.Browder, T. E.Cao, L.Cervenkov, D.Chekelian, V.Chen, A.Cheon, B. G.Chilikin, K.Cho, K.Choi, S-K.Choi, Y.Choudhury, S.Cinabro, D.Cunliffe, S.Dash, N.Di Carlo, S.Dingfelder, J.Dolezal, Z.Dong, T. V.Drasal, Z.Eidelman, S.Epifanov, D.Fast, J. E.Ferber, T.Garg, R.Gaur, V.Gabyshev, N.Garmash, A.Gelb, M.Giri, A.Goldenzweig, P.Guido, E.Haba, J.Hayasaka, K.Hayashii, H.Hirose, S.Hou, W-S.Iijima, T.Inami, K.Inguglia, G.Ishikawa, A.Itoh, R.Iwasaki, M.Iwasaki, Y.Jacobs, W. W.Jeon, H. B.Jia, S.Jin, Y.Joffe, D.Joo, K. K.Julius, T.Kawasaki, T.Kichimi, H.Kiesling, C.Kim, D. Y.Kim, H. J.Kim, J. B.Kim, K. T.Kim, S. H.Kinoshita, K.Kodys, P.Korpar, S.Kotchetkov, D.Krizan, P.Kroeger, R.Krokovny, P.Kuhr, T.Kulasiri, R.Kuzmin, A.Kwon, Y-J.Lange, J. S.Lee, I. S.Lee, S. C.Li, L. K.Li, Y. B.Gioi, L. LiLibby, J.Liventsev, D.Lubej, M.Luo, T.Masuda, M.Matsuda, T.Matvienko, D.Merola, M.Miyabayashi, K.Miyata, H.Mizuk, R.Mohanty, G. B.Moon, H. K.Mori, T.Mussa, R.Nakao, M.Nanut, T.Nath, K. J.Natkaniec, Z.Nayak, M.Niiyama, M.Nisar, N. K.Nishida, S.Ogawa, S.Okuno, S.Ono, H.Pakhlov, P.Pakhlova, G.Pal, B.Pardi, S.Park, H.Paul, S.Pestotnik, R.Piilonen, L. E.Popov, V.Prencipe, E.Rabusov, A.Ritter, M.Rostomyan, A.Russo, G.Sakai, Y.Salehi, M.Sandilya, S.Santelj, L.Sanuki, T.Savinov, V.Schneider, O.Schnell, G.Schwanda, C.Seino, Y.Senyo, K.Sevior, M. E.Shebalin, V.Shen, C. P.Shibata, T-A.Shiu, J-G.Shwartz, B.Simon, F.Singh, J. B.Sokolov, A.Solovieva, E.Staric, M.Strube, J. F.Sumihama, M.Sumisawa, K.Sumiyoshi, T.Sutcliffe, W.Takizawa, M.Tamponi, U.Tanida, K.Tenchini, F.Uchida, M.Uglov, T.Unno, Y.Uno, S.Urquijo, P.Vahsen, S. E.Van Hulse, C.Van Tonder, R.Varner, G.Vinokurova, A.Vorobyev, V.Vossen, A.Wang, B.Wang, C. H.Wang, P.Wang, X. L.Watanabe, M.Watanuki, S.Widmann, E.Won, E.Ye, H.Yin, J. H.Yuan, C. Z.Zhang, Z. P.Zhilich, V.Zhukova, V.Zhulanov, V.Zupanc, A.2018-12-182018-12-182018-12-182018-12-0310.1103/PhysRevLett.121.232001https://infoscience.epfl.ch/handle/20.500.14299/153060WOS:000451986100005We report the observation of gamma(2S) -> gamma eta(b)(1S) based on an analysis of the inclusive photon spectrum of 24.7 fb(-1) of e(+)e(-) collisions at the gamma(2s) center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We measure a branching fraction of B [gamma(2S) -> gamma eta(b)(1S)] = (6.1(-0.7-0.6)(+0.6+0.9) x 10(-4) and derive an eta(b) (1S) mass of 9394.8(-3.1-2.7)(+2.7+4.5) MeV/c(2), where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.Physics, MultidisciplinaryPhysicsj/psitext::journal::journal article::research article