Determination of the lifetime of bottom hadrons

We have measured the mean lifetime of the hadrons containing b quarks that are produced in e⁺{e}^{{{-}}}$ annihilation at {}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 τb=[1.29±{}0.20(stat) ±{}0.07(syst) ps]×{}(1.00±{}0.15), where the last factor is the systematic uncertainty in the scale.