Analysis of the Eta-pi-0-pi-o Final-state In Photon-photon Collisions

Karch, K.; Antreasyan, D.; Bartels, H. W.; Besset, D.; Bieler, C.; Bienlein, J. K.; Bizzeti, Andrea; Bloom, E. D.; Brock, I.; Brockmuller, K.; Cabenda, R.; Cartacci, A.; Cavallisforza, M.; Clare, R.; Compagnucci, A.; Conforto, G.; Cooper, S.; Cowan, R.; Coyne, D.; Engler, A.; Fairfield, K.; Folger, G.; Fridman, A.; Gaiser, J.; Gelphman, D.; Glaser, G.; Godfrey, G.; Graaf, K.; Heimlich, F. H.; Heinsius, F. H.; Hofstadter, R.; Irion, J.; Jakubowski, Z.; Janssen, H.; Keh, S.; Kiel, T.; Kilian, H.; Kirkbride, I.; Koiber, T.; Kobel, M.; Koch, W.; Konig, A. C.; Konigsmann, K.; Kraemer, R. W.; Kruger, S.; Landi, G.; Lee, R.; Leffler, S.; Lekebusch, R.; Lesiak, T.; Litke, A. M.; Lockman, W.; Lowe, S.; Lurz, B.; Marlow, D.; Marsiske, H.; Maschmann, W.; Mcbride, P.; Messing, F.; Metzger, W. J.; Meyer, H.; Monteleoni, B.; Muryn, B.; Nernst, R.; Niczyporuk, B.; Nowak, G.; Peck, C.; Pelfer, P. G.; Pollock, B.; Porter, F. C.; Prindle, D.; Ratoff, P.; Reidenbach, M.; Renger, B.; Rippich, C.; Scheer, M.; Schmitt, P.; Schotanus, J.; Schutte, J.; Schwarz, A.; Sievers, D.; Skwarnicki, T.; Stock, V.; Strauch, K.; Strohbusch, U.; Tompkins, J.; Trost, H. J.; Vanuitert, B.; Vandewalle, R. T.; Vogel, H.; Voigt, A.; Volland, U.; Wachs, K.; Wacker, K.; Walk, W.; Wegener, H.; Williams, D. A.; Zschorsch, P.

doi:10.1007/BF01881706

The reaction e+ e- --> e+e- eta-pi(0)pi(0) --> e+ e- 6-gamma has been analysed using the full data sample taken with the Crystal Ball detector at the DORIS II storage ring at DESY. The eta-pi(0)pi(0) invariant mass spectrum is dominated by the eta', for which we determine the radiative width GAMMA(gamma-gamma)(eta') to be (4.5 +/- 0.3 +/- 0.5) keV. Near 1.9 GeV/c2 we observe a second enhancement in the eta-pi(0)pi(0) mass distribution. Assuming that these events are created by the production and subsequent decay of a wide resonance X(1900), we have investigated the decay modes, the invariant mass distributions of the eta-pi(0) and pi(0)pi(0) subsystems and the angular distributions of the final state mesons. We find that the data is best described by J(PC) = 2-+. For this J(P) assignment the resonance parameters are GAMMA(gamma-gamma)(X) BR (X --> eta-pi-pi) = (0.95 +/- 0.27 +/- 0.20) keV, GAMMA(tot)(X) = (221 +/- 92 +/- 44) MeV, and M(X) = (1881 +/- 32 +/- 40) MeV/c2.

Analysis of the Eta-pi-0-pi-o Final-state In Photon-photon Collisions / K., K., D., A., H. W., B., D., B., C., B., J. K., B., Bizzeti, A., E. D., B., I., B., K., B., R., C., A., C., M., C., R., C., A., C., G., C., S., C., R., C., D., C., A., E., et al.. - In: ZEITSCHRIFT FÜR PHYSIK. C, PARTICLES AND FIELDS. - ISSN 0170-9739. - STAMPA. - 54:(1992), pp. 33-44. [10.1007/BF01881706]