Measurement of $\eta_c(1S), \eta_c(2S)$ and non-resonant $\eta' \pi^{+} \pi^{-}$ production via two-photon collisions
Creators: name: Xu, Q. N.
name: Adachi, I.
name: Aihara, H.
name: Al Said, S.
name: Asner, D. M.
name: Atmacan, H.
name: Aulchenko, V.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Badhrees, I.
name: Bakich, A. M.
name: Bansal, V.
name: Barberio, E.
name: Behera, P.
name: Berger, M.
name: Bhardwaj, V.
name: Bhuyan, B.
name: Biswal, J.
name: Bondar, A.
name: Bozek, A.
name: Bračko, M.
name: Červenkov, D.
name: Chen, A.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, K.
name: Choi, S.-K.
name: Choi, Y.
name: Cinabro, D.
name: Cunliffe, S.
name: Czank, T.
name: Dash, N.
name: Di Carlo, S.
name: Doležal, Z.
name: Drásal, Z.
name: Eidelman, S.
name: Epifanov, D.
name: Fast, J. E.
name: Ferber, T.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Gelb, M.
name: Goldenzweig, P.
name: Guan, Y.
name: Guido, E.
name: Haba, J.
name: Hayasaka, K.
name: Hayashii, H.
name: Hedges, M. T.
name: Hou, W.-S.
name: Inami, K.
name: Inguglia, G.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Jaegle, I.
name: Jeon, H. B.
name: Jin, Y.
name: Joo, K. K.
name: Julius, T.
name: Kaliyar, A. B.
name: Kang, K. H.
name: Karyan, G.
name: Kawasaki, T.
name: Kichimi, H.
name: Kiesling, C.
name: Kim, D. Y.
name: Kim, H. J.
name: Kim, J. B.
name: Kodyš, P.
name: Korpar, S.
name: Kotchetkov, D.
name: Križan, P.
name: Kroeger, R.
name: Krokovny, P.
name: Kulasiri, R.
name: Kwon, Y.-J.
name: Lee, I. S.
name: Lee, S. C.
name: Li, L. K.
name: Li, Y.
name: Li Gioi, L.
name: Libby, J.
name: Liventsev, D.
name: Lubej, M.
name: Luo, T.
name: Masuda, M.
name: Matsuda, T.
name: Matvienko, D.
name: Merola, M.
name: Miyabayashi, K.
name: Miyata, H.
name: Mizuk, R.
name: Moon, H. K.
name: Mori, T.
name: Mussa, R.
name: Nanut, T.
name: Nath, K. J.
name: Natkaniec, Z.
name: Nayak, M.
name: Nisar, N. K.
name: Nishida, S.
name: Okuno, S.
name: Ono, H.
name: Onuki, Y.
name: Pakhlov, P.
name: Pakhlova, G.
name: Pal, B.
name: Park, H.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Popov, V.
name: Ritter, M.
name: Rostomyan, A.
name: Russo, G.
name: Sakai, Y.
name: Salehi, M.
name: Sandilya, S.
name: Sanuki, T.
name: Savinov, V.
name: Schneider, O.
name: Schnell, G.
name: Schwanda, C.
name: Seino, Y.
name: Senyo, K.
name: Seon, O.
name: Sevior, M. E.
name: Shebalin, V.
name: Shen, C. P.
name: Shibata, T.-A.
name: Shimizu, N.
name: Shiu, J.-G.
name: Sokolov, A.
name: Solovieva, E.
name: Starič, M.
name: Strube, J. F.
name: Sumiyoshi, T.
name: Takizawa, M.
name: Tamponi, U.
name: Tanida, K.
name: Tenchini, F.
name: Uchida, M.
name: Uehara, S.
name: Uglov, T.
name: Unno, Y.
name: Uno, S.
name: Urquijo, P.
name: Van Hulse, C.
name: Varner, G.
name: Vinokurova, A.
name: Vorobyev, V.
name: Vossen, A.
name: Wang, B.
name: Wang, C. H.
name: Wang, M.-Z.
name: Wang, P.
name: Wang, X. L.
name: Watanabe, M.
name: Watanabe, Y.
name: Widmann, E.
name: Won, E.
name: Ye, Hua
name: Yuan, C. Z.
name: Yusa, Y.
name: Zakharov, S.
name: Zhang, C. C.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
name: Zhulanov, V.
name: Zupanc, A.
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2018
Subjects: electron positron: annihilation
electron positron: colliding beams
photon photon: interaction
eta/c(2980): photoproduction
eta/c(3590): photoproduction
eta(958): radiative decay
eta(958): hadronic decay
mass spectrum: (eta(958) pi+ pi-)
mass spectrum: (pi+ pi-)
mass: width
eta/c(2980): mass: measured
eta/c(2980): width: measured
eta/c(3590): mass: measured
eta/c(3590): width: measured
branching ratio
eta/c(2980): decay modes
statistical
exchange: two-photon
BELLE
KEK-B
channel cross section: measured
experimental results
eta/c(3590) --&gt; eta(958) pi+ pi-
eta(958) --&gt; photon rho(770)
eta(958) --&gt; eta pi+ pi-

description: We report the measurement of $\gamma \gamma \to \eta_{c}(1S), \eta_{c}(2S) \to \eta' \pi^+ \pi^-$ with $\eta'$ decays to $\gamma \rho$ and $\eta \pi^+ pi^-$ using 941 fb$^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The $\eta_{c}(1S)$ mass and width are measured to be $M = [2984.6\pm0.7 (stat.)\pm2.2 (syst.)] MeV/c^{2}$ and $\Gamma = [30.8^{+2.3}_{-2.2}~(stat.) \pm 2.5~(syst.)]$ MeV, respectively. First observation of $\eta_{c}(2S) \to \eta' pi^+ pi^-$ with a significance of 5.5$\sigma$ including systematic error is obtained, and the $\eta_{c}(2S)$ mass is measured to be $M = [3635.1\pm3.7~(stat.)\pm2.9~(syst.)] MeV/c^{2}$. The products of the two-photon decay width and branching fraction (B) of decays to $\eta' pi^+ pi^-$ are determined to be $\Gamma_{\gamma \gamma}B = [65.4\pm2.6~(stat.)\pm6.9~(syst.)]$ eV for $\eta_{c}(1S)$ and $[5.6^{+1.2}_{-1.1}~(stat.)\pm1.1~(syst.)]$ eV for $\eta_{c}(2S)$. A new decay mode for the $\eta_{c}(1S) \to \eta' f_{0}(2080)$ with $f_{0}(2080) \to \pi^+ pi^-$ is observed with a statistical significance of 20$\sigma$. The $f_{0}(2080)$ mass and width are determined to be $M = [2083^{+63}_{-66}~(stat.)\pm 32~(syst.)] MeV/c^{2}$ and $\Gamma = [178^{+60}_{-178}~(stat.) \pm 55~(syst.)]$ MeV. The cross sections for $\gamma \gamma \to \eta' pi^+ pi^-$ and $\eta' f_{2}(1270)$ are measured for the first time.