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 Zeitschrift für Physik C 75 (1997) 397-407
 Improved measurement of the $B^0_d$--$\overline{B}^0_d$ Oscillation frequency
 ALEPH Collaboration(s)
 (1997)
 The time dependence of $B^0_d--\bar{B}^0_d$ oscillations is measured by the ALEPH experiment at LEP, using three techniques, two of which are updates of previous measurements. In all cases the charge of the decaying $b$ quark and its decay time are measured in one hemisphere of the event the quark charge at production is tagged mainly using the opposite hemisphere. The first method uses the charge correlation between a $D^{*-}$ and a lepton in the opposite hemisphere; if no lepton is present, the produced quark charge is determined from the hemisphere charges. In the second method, the decay time is measured using a lepton in one hemisphere and the initial state is inferred from the opposite-hemisphere jet charge. The third method uses a lepton in each hemisphere. The data used were collected from 1991 to 1994. The combined result is $\Delta m_d = 0.436\pm 0.033\, {\rm ps}^{-1}$
 Thème(s) : Physique/Physique des Hautes Energies - Expérience
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 in2p3-00005700, version 1 http://hal.in2p3.fr/in2p3-00005700 oai:hal.in2p3.fr:in2p3-00005700 Contributeur : Magali Damoiseaux <> Soumis le : Mardi 25 Juillet 2000, 12:31:38 Dernière modification le : Jeudi 2 Juin 2005, 17:12:50