Observation of the radiative decays of $Υ(1S)$ to $χ_{c1}$
Creators: name: Katrenko, P.
name: Adachi, I.
name: Aihara, H.
name: Said, S. Al
name: Asner, D. M.
name: Aushev, T.
name: Badhrees, I.
name: Bahinipati, S.
name: Behera, P.
name: Beleno, C.
name: Bennett, J.
name: Bhardwaj, V.
name: Bhuyan, B.
name: Biswal, J.
name: Bobrov, A.
name: Bonvicini, G.
name: Bracko, M.
name: Campajola, M.
name: Cao, L.
name: Cervenkov, D.
name: Chekelian, V.
name: Chen, A.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, H. E.
name: Cho, K.
name: Choi, S. -K.
name: Choi, Y.
name: Choudhury, S.
name: Cinabro, D.
name: Cunliffe, S.
name: Di Capua, F.
name: Di Carlo, S.
name: Dolezal, Z.
name: Dong, T. V.
name: Eidelman, S.
name: Epifanov, D.
name: Fast, J. E.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Giri, A.
name: Goldenzweig, P.
name: Golob, B.
name: Grzymkowska, O.
name: Hartbrich, O.
name: Hayasaka, K.
name: Hayashii, H.
name: Hou, W. -S.
name: Iijima, T.
name: Inami, K.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Jacobs, W. W.
name: Jeon, H. B.
name: Jia, S.
name: Jin, Y.
name: Joffe, D.
name: Joo, K. K.
name: Karyan, G.
name: Kichimi, H.
name: Kim, D. Y.
name: Kim, K. T.
name: Kim, S. H.
name: Kinoshita, K.
name: Kodys, P.
name: Korpar, S.
name: Kroeger, R.
name: Kuhr, T.
name: Lee, I. S.
name: Lee, S. C.
name: Lewis, P.
name: Li, Y. B.
name: Gioi, L. Li
name: Libby, J.
name: Lieret, K.
name: MacQueen, C.
name: Masuda, M.
name: Matsuda, T.
name: Matvienko, D.
name: Merola, M.
name: Miyabayashi, K.
name: Miyata, H.
name: Mizuk, R.
name: Mohanty, G. B.
name: Moon, T. J.
name: Mori, T.
name: Mussa, R.
name: Nakano, E.
name: Nakano, T.
name: Nakao, M.
name: Nayak, M.
name: Nisar, N. K.
name: Nishida, S.
name: Nishimura, K.
name: Ono, H.
name: Onuki, Y.
name: Oskin, P.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pang, T.
name: Pardi, S.
name: Park, C. W.
name: Park, H.
name: Park, S. -H.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Popov, V.
name: Prencipe, E.
name: Prim, M. T.
name: Ritter, M.
name: Rostomyan, A.
name: Rout, N.
name: Russo, G.
name: Sahoo, D.
name: Sakai, Y.
name: Sandilya, S.
name: Sanuki, T.
name: Savinov, V.
name: Schneider, O.
name: Schnell, G.
name: Schueler, J.
name: Schwanda, C.
name: Seino, Y.
name: Senyo, K.
name: Sevior, M. E.
name: Shen, C. P.
name: Shiu, J. -G.
name: Solovieva, E.
name: Staric, M.
name: Stottler, Z. S.
name: Sumiyoshi, T.
name: Sutcliffe, W.
name: Takizawa, M.
name: Tamponi, U.
name: Tanida, K.
name: Tenchini, F.
name: Trabelsi, K.
name: Uchida, M.
name: Uehara, S.
name: Uglov, T.
name: Unno, Y.
name: Uno, S.
name: Urquijo, P.
name: Usov, Y.
name: Van Tonder, R.
name: Varner, G.
name: Vossen, A.
name: Wang, B.
name: Wang, C. H.
name: Wang, M. -Z.
name: Wang, P.
name: Wang, X. L.
name: Won, E.
name: Yang, S. B.
name: Ye, H.
name: Yelton, J.
name: Yin, J. H.
name: Yuan, C. Z.
name: Yusa, Y.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
Publisher: name: arXiv
Year: 2019
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the first observation of the radiative decay of the $Υ(1S)$ into a charmonium state. The statistical significance of the observed signal of $Υ(1S) \to γχ_{c1}$ is 6.3 standard deviations including systematics. The branching fraction is calculated to be Br($Υ(1S) \to γχ_{c1}$) = (4.7^{+2.4}_{-1.8} (stat) ^{+0.4}_{-0.5} (sys)) * 10^{-5}. We also searched for $Υ(1S)$ radiative decays into $χ_{c0,2}$ and $η_c(1S,2S)$ and set upper limits on their branching fractions. These results are obtained from a 24.9 fb^{-1} data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider at a center-of-mass energy equal to the $Υ(2S)$ mass using $Υ(1S)$ tagging by the $Υ(2S) \to Υ(1S) π^+π^-$ transitions.
description: 7pages, 3 figures