Volume 160B, number 4,5 PHYSICS LETTERS 10 October 1985 RADIATIVE DECAYS OF THE T(2S) INTO THE THREE Xb STATES The ARGUS collaboration H. ALBRECHT, U. BINDER, G. HARDER, I. LEMBKE-KOPPITZ, A. PHILIPP, W. SCHMIDT-PARZEFALL, H. SCHRODER, H.D. SCHULZ, R. WURTH DESY, Hamburg, Fed. Rep. Germany A. DRESCHER, B. GRAWE, U. MATTHIESEN, H. SCHECK, J. SPENGLER, D. WEGENER Institut for Physik, Universit?ttDortmund 1, Dortmund, Fed. Rep. Germany K.R. SCHUBERT, J. STIEWE, R. WALDI, S. WESELER lnstitut fOr Hochenergiephysik, UnioersitgttHeidelberg 1, Heidelberg, Fed. Rep. Germany N.N. BROWN 2, K.W. EDWARDS 3, W.R. FRISKEN 4, Ch. FUKUNAGA 4, D.J. GILKINSON 5, 5 4 3 5 5 D.M. GINGRICH , M. GODDARD , H. KAPITZA , P.C.H. KIM , R. KUTSCHKE , 5 5 2 2 5 D.B. MACFARLANE , J.A. McKENNA , K.W. McLEAN , A.W. NILSSON , R.S. ORR , P. PADLEY 5, P.M. PATEL 2, J.D. PRENTICE 5, H.C.J. SEYWERD 5, B.J. STACEY 5, T.S. YOON 5, J.C. YUN 3 Institute of Particle Physics 6, Canada R. AMMAR, D. COPPAGE, R. DAVIS, S. KANEKAL, N. KWAK University of Kansas 7, Lawrence, KS, USA G. KERNEL, M. PLESKO J. Stefan Institute and Department of Physics, University of Ljubljana 8, Ljubljana, Yugoslavia L. JONSSON, Y. OKU Institute of Physics, University of Lund 9, Lurid, Sweden A. BABAEV, M. DANILOV, A. GOLUTVIN, V. LUBIMOV, V. MATVEEV, V. NAGOVITSIN, V. RYLTSOV, A. SEMENOV, V. SHEVCHENKO, V. SOLOSHENKO, V. SOPOV, I. TICHOMIROV, Yu. ZAITSEV Institute of Theoretical and Experimental Physics, Moscow, USSR R. CHILDERS, C.W. DARDEN and H. GENNOW 10 University of South Carolina 11, Columbia, SC, USA Received 23 July 1985 The ARGUS detector at the e+e - storage ring DORIS II has been used as'a pair spectrometer to study the photon transitions in the reaction T(2S)~ YXb(13p2.1.0). Three photon lines were observed with energies (110.6+0.3+0.9) MeV, (131.7+0.3+1.1) MeV and (162.1+0.5+1.4) MeV, respectively. The corresponding branching ratios were found to be (9.8 + 2.1 + 2.4)%, (9.1 + 1.8 + 2.2)% and (6.4 + 1.4 + 1.6)%. Upper limits for full widths at the 90% confidence limit are 1.0 MeV for the Xb(13p2) and 2.6MeV for the other two states. For footnotes see next page. 0370-2693/85/$ 03.30 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division) 331