Determination of the lifetime of bottom hadrons

Abstract

We have measured the mean lifetime of the hadrons containing b quarks that are produced in ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ annihilation at \ensuremath{\surd}s =29 GeV. We use the full sample of data collected by the MAC detector at the SLAC storage ring, PEP, including those recently acquired with a precision vertex detector. The result is ${\ensuremath{\tau}}_{b}$=[1.29\ifmmode\pm\else\textpm\fi{}0.20(stat) \ifmmode\pm\else\textpm\fi{}0.07(syst) ps]\ifmmode\times\else\texttimes\fi{}(1.00\ifmmode\pm\else\textpm\fi{}0.15), where the last factor is the systematic uncertainty in the scale.