We acknowledge in particular the support of Austrian Federal Ministry of Education, Science and Culture, GZ 616.364/2-III/2a/98, FNRS–FWO, Flanders Institute to encourage scientific and technological research in the industry (IWT), Belgium, FINEP, CNPq, CAPES, FUJB and FAPERJ, Brazil, Czech Ministry of Industry and Trade, GA CR 202/99/1362, Commission of the European Communities (DG XII), Direction des Sciences de la Matiere, CEA, France, Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie, Germany, General Secretariat for Research and Technology, Greece, National Science Foundation (NWO) and Foundation for Research on Matter (FOM), The Netherlands, Norwegian Research Council, State Committee for Scientific Research, Poland, SPUB-M/CERN/PO3/DZ296/2000, SPUB-M/CERN/PO3/DZ297/2000, 2P03B 104 19 and 2P03B 69 23(2002-2004) JNICT–Junta Nacional de Investigaçao Cientifica e Tecnologica, Portugal, Vedecka grantova agentura MS SR, Slovakia, Nr. 95/5195/134, Ministry of Science and Technology of the Republic of Slovenia, CICYT, Spain, AEN99-0950 and AEN99-0761, The Swedish Natural Science Research Council, Particle Physics and Astronomy Research Council, UK, Department of Energy, USA, DE-FG02-01ER41155.

Final results from the DELPHI Collaboration on the lifetime of B+ and B0 mesons and the mean b-hadron lifetime, are presented using the data collected at the Z0 peak in 1994 and 1995. Elaborate, inclusive, secondary vertexing methods have been employed to ensure a b-hadron reconstruction with good efficiency. To separate samples of B+ and B0 mesons, high performance neural network techniques are used that achieve very high purity signals. The results obtained are: τB+ = 1.624±0.014 (stat)±0.018 (syst) ps τB0 = 1.531±0.021 (stat)±0.031 (syst) ps τB+ τB0 = 1.060±0.021 (stat)±0.024 (syst) and for the average b-hadron lifetime: τb = 1.570±0.005 (stat)±0.008 (syst) ps.

DELPHI Collaboration: et al.

arXiv:hep-ex/0401025v1

CERN–EP/2003-065

Peer reviewed