Search for exclusive decays of the Λb baryon and measurement of its mass

• Published in: Physics letters. B 1996-05, Vol.374 (4), p.351-361
• Main Authors: Ajinenko, I, Alekseev, G.D, Amato, S, Barate, R, Bartl, W, Baubillier, M, Becks, K-H, Belokopytov, Yu, Bolognese, T, Bosworth, S, Bozzo, M, Brand, K.D, Cabrera, S, Canepa, M, Cao, F, Castillo Gimenez, M.V, Charpentier, Ph, Chauveau, J, Cosme, G, Crennell, D, Dahm, J, Eigen, G, Ekspong, G, Engel, J-P, Foeth, H, Gamba, D, Gazis, E.N, Gele, D, Gumenyuk, S, Hahn, F, Henriques, R, Herquet, P, Herr, H, Holmgren, S.-O, Houlden, M, Janik, R, Jean-Marie, B, Kapusta, F, Khokhlov, Yu, Koene, B, Korcyl, K, Krumstein, Z, Krupinski, W, Kurvinen, K, Langefeld, P, Leder, G, Legan, C.K, Lemonne, J, Lepeltier, V, Loerstad, B, Loukas, D, Marco, R, Masik, J, Matthiae, G, Meyer, S, Mundim, L.M, Murray, W.J, Navas, S, Nicolaidou, R, Olshevski, A.G, Papageorgiou, K, Parodi, F, Perrotta, A, Petridou, C, Phillips, H.T, Piana, G, Podobrin, O, Privitera, P, Pukhaeva, N, Ragazzi, S, Rahmani, H, Regler, M, Richard, F, Rybicki, K, Sanchez, J, Seitz, A, Smadja, G, Spiriti, E, Strauss, J, Strub, R, Stugu, B, Szeptycka, M, Tchikilev, O, Treille, D, Tsirou, A, Tyapkin, I.A, Ueberschaer, B, Vander Velde, C, Van Apeldoorn, G.W, Van Dam, P, Venus, W, Vincent, P, Vodopyanov, A.S, Wahlen, H, Wielers, M, Wilkinson, G.R, Williams, W.S.C, Zalewska, A, Zontar, D, Zumerle, G
• Format: Article
• Language: English
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(96)00306-1

A search for fully reconstructed Λ b 0 beauty baryons is performed using about 3 million Z decays collected with the DELPHI detector at LEP. The analysis relies on the combined use of the accurate tracking and of the hadron identification capabilities of DELPHI. A total of four events has been found, three in the Λ c + π − channel and one in the Λ c + a 1 − channel over a small background. The Λ b 0 beauty baryon mass is measured to be (5668 ± 16 (stat.) ± 8 (syst.)) MeV/c 2.