January 1, 2004 Journal article Open Access

b-tagging in DELPHI at LEP

M. Chapkin; Fabrizio Ferro; Th D. Papadopoulou; B. Dalmagne; M. Trochimczuk; M. J. Bates; A. Pullia; L. Berntzon; T. Allmendinger; M. Pimenta; Borut Paul Kerševan; P. D. Johansson; G. Grosdidier; Ugo Amaldi; P. Bambade; R. Keranen; J.H. Bibby; G. Vegni; Luc Pape; S. Todorovova; G. Cosme; Hans Dijkstra; Marco Costa; Vincent Hedberg; Markus Elsing; N. Tinti; I. A. Tyapkin; A. Petrolini; R. Sekulin; A. Di Simone; J. J. Gomez Y Cadenas; J. J. Gomez Y Cadenas; W. A. Mitaroff; Nicola Amapane; P. Collins; Andrea Perrotta; G. Myatt; P. Verdier; P.D. Jonsson; P. Buschmann; B. Muryn; R. Barbier; A. De Angelis; A. De Angelis; M. Karlsson; P. Bruckman; L. Vitale; L. Vitale; P. J. Holt; T. Podobnik; T. Podobnik; V. Obraztsov; S. Almehed; G. Tristram; A. N. Sisakian; W. Liebig; Tord Ekelof; Wojciech Kucewicz; Tiziano Rovelli; A. M. Segar; D. Ryabtchikov; Krzysztof Nawrocki; J. M. Heuser; J. Timmermans; K. Osterberg; S. U. Chung; Georgios Fanourakis; E. Piotto; V.A. Uvarov; P. Branchini; L. Pieri; N. Anjos; M. Gandelman; Alberto Benvenuti; G. Wilkinson; B. Marechal; A. Ballestrero; J. MacNaughton; Ernesto Migliore; Piotr Zalewski; Paolo Checchia; Phillip Allport; J. H. Wickens; J. H. Wickens; A. J. Washbrook; A. Norman; J. M. Lopez; José Salt; P. Poropat; Chiara Mariotti; J. W. Lamsa; H. Foeth; J. A. Hernando; M. Bonesini; S. Paiano; V. Poireau; M. A. Winter; A. Oyanguren; Fabrizio Parodi; J.Gh. Lopes; A. Savoy-Navarro; P. Tyapkin; Diego Rodriguez; J. D'Hondt; J. D'Hondt; F. Fulda-Quenzer; P.S.L. Booth; B. Åsman; Marco Paganoni; Valeriy Pozdniakov; Paolo Ronchese; T. Alderweireld; T. Alderweireld; Antonio Baroncelli; A. Behrmann; Demetrios Loukas; Anna Lipniacka; Clara Troncon; Y. Arnoud; K. Hultqvist; J. Piedra; A. Van Lysebetten; A. Van Lysebetten; B. Tome; V. Ruhlmann-Kleider; G. Polok; H. Palka; Gareth J. Barker; Rosy Nicolaidou; U. Mjoernmark; P. Niezurawski; D. Moraes; Javier Cuevas; G. Eigen; J. Kurowska; N. De Maria; L. Jungermann; Ahmimed Ouraou; Tomasz Szumlak; B. Golob; B. Golob; C. Joram; J. Fernandez; Tiziano Camporesi; G. Borisov; M. Tyndel; L. Leinonen; F. Couchot; G. Kernel; G. Kernel; A. Zintchenko; Allan Hallgren; R. Mc Nulty; M. Mazzucato; William Trischuk; R. Monge; P. Jalocha; Per Jönsson; A. Nygren; Francesca Romana Cavallo; Petar Adzic; Z. Krumstein; N. J. Kjaer; Ulrich Parzefall; K. Cieslik; W. T. Meyer; A. Passeri; J. Ridky; Andre Augustinus; V. Lepeltier; Martino Margoni; C. Matteuzzi; L. Lyons; M. Baubillier; Achille Stocchi; B. Bouquet; Ph. Gavillet; A. Zalewska; P. Biffi; T. J. V. Bowcock; R. Sosnowski; T. Moa; Krzysztof Doroba; E. Brodet; P. Abreu; M. Berggren; T. Albrecht; U. Mueller; B. De Lotto; B. De Lotto; Pablo Tortosa; J. M. Brunet; E. Fokitis; C. Martinez-Rivero; P. Lutz; E. K. Johansson; R. Contri; Nektarios Benekos; Manolis Dris; S. Haug; Nathalie Besson; Andre Sopczak; Paolo Morettini; Oxana Smirnova; Mattias Ellert; Petr Travnicek; Klaus Moenig; Massimo Caccia; Daniel Jeans; Rupert Leitner; Antonio Ferrer; Guillelmo Gomez-Ceballos; Francisco Matorras; Jiri Chudoba

Abstract: The standard method used for tagging b-hadrons in the DELPHI experiment at the CERN LEP Collider is discussed in detail. The main ingredient of b-tagging is the impact parameters of tracks, which relies mostly on the vertex detector. Additional information, such as the mass of particles associated to a secondary vertex, significantly improves the selection efficiency and the background suppression. The paper describes various discriminating variables used for the tagging and the procedure of their combination. In addition, applications of b-tagging to some physics analyses, which depend crucially on the performance and reliability of b-tagging, are described briefly.