Observation of a fully reconstructed D0 Dobar pair with long proper lifetime in a high resolution hydrogen bubble chamber and the European Hybrid Spectrometer

Adeva, B.; Aguilar Benítez, M.; Allison, W.; Bagnaia, P.; Baldo, B.; Barone, L.; Walter, Bartl; Bergier, A.; Bettini, Alessandro; Bizzarri, R.; Boratav, M.; Borreani, G.; Bruyant, F.; Edoardo, Castelli; Checchia, P.; Chliapnikov, P. V.; Ciapetti, G.; Cooremans Bertrand, G.; Crennell, D. J.; Cresti, Marcello; Crijns, F.; Di Capua, E.; Heinz, Dibon; Dionisi, C.; Dolbeau, J.; Dumarchez, J.; Etienne, F.; Ferrando, A.; Fisher Colin, M.; Frühwirth, R.; Gatignon, L.; Grard, F.; Hartjes, F.; Herquet, P.; Hervé, A.; Holmgren, S. O.; Josef, Hrubec; Hughes, P.; Johansson, K. E.; Kesteman, J.; Kistenev, E. P.; Kittel, E. W.; Kuhn, D.; Kurtz, N.; Ladrón De Guevara, P.; Lecoq, P.; Lemonne, J.; Lesceux, J.; Leutz, H.; Lipari, P.; Loverre, P. F.; Marchetto, F.; Marin, J.; Manfred, Markytan; Marzano, F.; Mazzucato, M.; Menichetti, E.; Michalon, A.; Michalon Mentzer, M.; Moa, T.; Lucien, Montanet; Neuhofer, G.; Nguyen, H.; Nilsson, S.; Paler, K.; Pascoli, D.; Peruzzo, Luigi; Pilette, P.; Piredda, G.; Poljakov, B.; Poppleton, A.; Poropat, P.; Paul, Porth; Meinhard, Regler; Reucroft, S.; Robb, L.; Rossi, Paolo; Rubio, J.; Sartori, G.; Sessa, M. I.; Athanase, Stergiou; Subramanian, A.; Stefaan, Tavernier; Toet, D. Z.; Touboul, M.; Touchard, A. M.; Troncon, C.; Van Immerseel, M.; Ventura, Luigi; Vilain, P.; Voltolini, C.; Wickens, J.; Zanello, D.; Zanello, L.; Zholobov, G.; Zotto, Pierluigi; Zumerle, Gianni

doi:10.1016/0370-2693(81)90877-7

In an experiment with 360 GeV/c π- beam at the CERN SPS using the high resolution hydrogen bubble chamber LEBC and the European Hybrid Spectrometer, an event has been observed of the type π-p→D0D0 + 8 prongs. The fully reconstructed decay modes are D0→K-π+π0π0 and D0→K+π+π-π-, with all six charged tracks being detected in the spectrometer and all four photons from the π0 decays detected in the lead glass gamma detection system. The D0 has momentum 119.0 ± 0.6 GeV/c, xF = 0.31, length 4.1 ± 0.1 mm and proper lifetime (2.1 ± 0.1) × 10-13 s. The D0 has momentum 78.5 ± 0.3 GeV/c, xF = 0.19, length 7.5 ± 0.1 mm and proper lifetime (5.9 ± 0.1) × 10-13 s. © 1981.