An improved measurement of the forward-backward asymmetry in Z → bb¯ decays is presented, based on a sample of 4.1 million hadronic Z decays collected by ALEPH between 1991 and 1995. Data are analysed as a function of polar angle of the event axis and b purity. The event tagging efficiency and mean b-jet hemisphere charge are measured directly from data. From the measured forward-backward jet charge asymmetry, the b quark asymmetry at √s = mZ is determined to be: AbAB = 0.1017 ± 0.0038(stat.) ± 0.0032(syst.) In the context of the Standard Model this corresponds to a value of the effective weak mixing angle of sin2θeffW = 0.23109 ± 0.00096.
|Original language||English (US)|
|Number of pages||14|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|State||Published - Apr 30 1998|
ASJC Scopus subject areas
- Nuclear and High Energy Physics