Direct search for light gluinos

Fanti, V.; Lai, A.; Musa, L.; Marras, D.; Nappi, A.; Hay, B.; Moore, R. W.; Moore, K. N.; Munday, D. J.; Needham, M. D.; Parker, M. A.; White, T. O.; Wotton, S.; Andersen, J.; Barr, G.; Bocquet, G.; Bremer, J.; Ceccucci, A.; Cundy, D.; Doble, N.; Fischer, G.; Funk, W.; Gatignon, L.; Gianoli, A.; Gonidec, A.; Govi, G.; Grafstrom, P.; Kubischta, W.; Luitz, S.; Kesseler, G.; Matheys, J. P.; Norton, A.; Palestini, S.; Panzersteindel, B.; Schinzel, D.; Taureg, H.; Velasco, M.; Vossnack, O.; Wahl, H.; Wirrer, G.; Kekelidze, V.; Mestvirishvili, A.; Potrebenikov, Y. U.; Tatishvili, G.; Tkatchev, A.; Zinchenko, A.; Boyle, O.; Martin, V. J.; Knowles, I. G.; Parsons, H. L. C.; Dalpiaz, Pietro; Duclos, J.; Frabetti, P. L.; Martini, Mara; Petrucci, Ferruccio Carlo; Porcu, M.; Savrie', Mauro; Bizzeti, A.; Calvetti, M.; Graziani, G.; Iacopini, E.; Lenti, M.; Michetti, A.; Becker, H. G.; Blumer, H.; Buchholz, P.; Coward, D.; Ebersberger, C.; Fox, H.; Kalter, A.; Kleinknecht, K.; Koch, U.; Kopke, L.; Renk, B.; Scheidt, J.; Schmidt, J.; Schonharting, V.; Schu, I.; Wilhelm, R.; Winharting, A.; Wittgen, M.; Chollet, J. C.; Crepe, S.; Fayard, L.

doi:10.1016/S0370-2693(98)01459-2

We present the results for a direct search for light gluinos through the appearance of eta --> 3 pi0 with high transverse momentum in the vacuum tank of the NA48 experiment at CERN. We find one event within a lifetime range of 10^-9 – 10^-3 s and another one between 10^-10 – 10^-9 s. Both events are consistent with the expected background from neutrons in the beam, produced by 450 GeV protons impinging on the Be targets, which interact with the residual air in the tank. From these data we give limits on the production of the hypothetical gg~ bound state, the R0 hadron, and its R0 --> eta gamma~ decay in the R0 mass range between 1 and 5 GeV.