| Approximately four million hadronic Z decays were recorded with the ALEPH detector at LEP from 1991 through 1995. Using this data set, the lifetime of the L0b baryon is measured. The L0b is reconstructed in the semileptonic decay mode L0b→L+ cℓ-n ℓX ; the L+c is reconstructed in the semileptonic decay mode L+c→Lℓ +nℓX as well as the four hadronic decay modes L+c→pK- p+,pK 0,Lp+, and Lp+p-p + . From the L+c semileptonic decay sample of 46 Lℓ+ℓ- combinations the lifetime is measured to be t&parl0;L0b&parr0; = ( 1.30+0.26-0.21 (statistical) +/- 0.04 (systematic)) ps. From the L+c hadronic decay sample of 193 L+cℓ- combinations the lifetime is measured to be t&parl0;L0b&parr0; = ( 1.18+0.13-0.12 (statistical) +/- 0.03 (systematic)) ps. The combined value is t&parl0;L0b&parr0; = (1.21 +/- 0.11) ps. |
