Measurement of radiative widths of $a_2(1320)$ and $π_2(1670)$
Creators: name: Adolph, C.
name: Akhunzyanov, R.
name: Alekseev, M. G.
name: Alexeev, G. D.
name: Amoroso, A.
name: Andrieux, V.
name: Anosov, V.
name: Austregesilo, A.
name: Badelek, B.
name: Balestra, F.
name: Barth, J.
name: Baum, G.
name: Beck, R.
name: Bedfer, Y.
name: Berlin, A.
name: Bernhard, J.
name: Bicker, K.
name: Bieling, J.
name: Birsa, R.
name: Bisplinghoff, J.
name: Bodlak, M.
name: Boer, M.
name: Bordalo, P.
name: Bradamante, F.
name: Braun, C.
name: Bressan, A.
name: Buechele, M.
name: Burtin, E.
name: Capozza, L.
name: Chiosso, M.
name: Chung, S. U.
name: Cicuttin, A.
name: Crespo, M. L.
name: Curiel, Q.
name: Torre, S. Dalla
name: Dasgupta, S. S.
name: Dasgupta, S.
name: Denisov, O. Yu.
name: Donskov, S. V.
name: Doshita, N.
name: Duic, V.
name: Duennweber, W.
name: Dziewiecki, M.
name: Efremov, A.
name: Elia, C.
name: Eversheim, P. D.
name: Eyrich, W.
name: Faessler, M.
name: Ferrero, A.
name: Filin, A.
name: Finger, M.
name: Finger~jr., M.
name: Fischer, H.
name: Franco, C.
name: du~Fresne~von~Hohenesche, N.
name: Friedrich, J. M.
name: Frolov, V.
name: Gautheron, F.
name: Gavrichtchouk, O. P.
name: Gerassimov, S.
name: Geyer, R.
name: Gnesi, I.
name: Gobbo, B.
name: Goertz, S.
name: Gorzellik, M.
name: Grabmueller, S.
name: Grasso, A.
name: Grube, B.
name: Guskov, A.
name: Guthoerl, T.
name: Haas, F.
name: von Harrach, D.
name: Hahne, D.
name: Hashimoto, R.
name: Heinsius, F. H.
name: Herrmann, F.
name: Hinterberger, F.
name: Hoeppner, Ch.
name: Horikawa, N.
name: d'Hose, N.
name: Huber, S.
name: Ishimoto, S.
name: Ivanov, A.
name: Ivanshin, Yu.
name: Iwata, T.
name: Jahn, R.
name: Jary, V.
name: Jasinski, P.
name: Joerg, P.
name: Joosten, R.
name: Kabuss, E.
name: Ketzer, B.
name: Khaustov, G. V.
name: Khokhlov, Yu. A.
name: Kisselev, Yu.
name: Klein, F.
name: Klimaszewski, K.
name: Koivuniemi, J. H.
name: Kolosov, V. N.
name: Kondo, K.
name: Koenigsmann, K.
name: Konorov, I.
name: Konstantinov, V. F.
name: Kotzinian, A. M.
name: Kouznetsov, O.
name: Kral, Z.
name: Kraemer, M.
name: Kroumchtein, Z. V.
name: Kuchinski, N.
name: Kunne, F.
name: Kurek, K.
name: Kurjata, R. P.
name: Lednev, A. A.
name: Lehmann, A.
name: Levorato, S.
name: Lichtenstadt, J.
name: Maggiora, A.
name: Magnon, A.
name: Makke, N.
name: Mallot, G. K.
name: Marchand, C.
name: Martin, A.
name: Marzec, J.
name: Matousek, J.
name: Matsuda, H.
name: Matsuda, T.
name: Meshcheryakov, G.
name: Meyer, W.
name: Michigami, T.
name: Mikhailov, Yu. V.
name: Miyachi, Y.
name: Nagaytsev, A.
name: Nagel, T.
name: Nerling, F.
name: Neubert, S.
name: Neyret, D.
name: Nikolaenko, V. I.
name: Novy, J.
name: Nowak, W. -D.
name: Nunes, A. S.
name: Orlov, I.
name: Olshevsky, A. G.
name: Ostrick, M.
name: Panknin, R.
name: Panzieri, D.
name: Parsamyan, B.
name: Paul, S.
name: Pesek, M.
name: Platchkov, S.
name: Pochodzalla, J.
name: Polyakov, V. A.
name: Pretz, J.
name: Quaresma, M.
name: Quintans, C.
name: Ramos, S.
name: Reicherz, G.
name: Rocco, E.
name: Rychter, A.
name: Rossiyskaya, N. S.
name: Ryabchikov, D. I.
name: Samoylenko, V. D.
name: Sandacz, A.
name: Sarkar, S.
name: Savin, I. A.
name: Sbrizzai, G.
name: Schiavon, P.
name: Schill, C.
name: Schlueter, T.
name: Schmidt, A.
name: Schmidt, K.
name: Schmieden, H.
name: Schoenning, K.
name: Schopferer, S.
name: Schott, M.
name: Shevchenko, O. Yu.
name: Silva, L.
name: Sinha, L.
name: Sirtl, S.
name: Slunecka, M.
name: Sosio, S.
name: Sozzi, F.
name: Srnka, A.
name: Steiger, L.
name: Stolarski, M.
name: Sulc, M.
name: Sulej, R.
name: Suzuki, H.
name: Szabelski, A.
name: Szameitat, T.
name: Sznajder, P.
name: Takekawa, S.
name: ter~Wolbeek, J.
name: Tessaro, S.
name: Tessarotto, F.
name: Thibaud, F.
name: Uhl, S.
name: Uman, I.
name: Vandenbroucke, M.
name: Virius, M.
name: Vondra, J.
name: Wang, L.
name: Weisrock, T.
name: Wilfert, M.
name: Windmolders, R.
name: Wollny, H.
name: Zaremba, K.
name: Zavertyaev, M.
name: Zemlyanichkina, E.
name: Ziembicki., M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The COMPASS Collaboration at CERN has investigated the reaction $π^- γ\rightarrow π^-π^-π^+$ embedded in the Primakoff reaction of $190~\textrm{GeV}$ pions scattering in the Coulomb field of a lead target, $π^- \text{Pb} \rightarrow π^-π^-π^+ \text{Pb}$. Exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at momentum transfer below $0.001~(\text{GeV}/c)^2$. Using a partial-wave analysis the amplitudes and relative phases of the $a_2(1320)$ and $π_2(1670)$ mesons have been extracted, and the Coulomb and the diffractive contributions have been disentangled. Measuring absolute production cross sections we have determined the radiative width of the $a_2(1320)$ to be $Γ_0(a_2(1320) \rightarrow πγ) = (358 \pm 6_{\textrm{stat}} \pm 42_{\textrm{syst}})~\textrm{keV}$. As the first measurement, $Γ_0(π_2(1670) \rightarrow πγ) = (181 \pm 11_{\textrm{stat}} \pm 27_{\textrm{syst}})~\textrm{keV} \cdot (\textrm{BR}^{\textrm{PDG}}_{f_2 π}/\textrm{BR}_{f_2 π})$ is obtained for the radiative width of the $π_2(1670)$, where in this analysis the branching ratio $\textrm{BR}^{\textrm{PDG}}_{f_2 π}=0.56$ has been used. We compare these values to previous measurements and theoretical predictions.
description: 27 pages, 12 figures and 3 tables