Measurement of the average b-baryon lifetime and the product branching ratio {\boldmath {{f({\mathrm{b}} \rightarrow \Lambda_{\mathrm{b}}) \cdot BR(\Lambda_{\mathrm{b}} \rightarrow \Lambda \ell^- \bar{\nu} \mathrm{X})}}}

Measurement of the average b-baryon lifetime and the product branching ratio {\boldmath {{f({\mathrm{b}} \rightarrow \Lambda_{\mathrm{b}}) \cdot BR(\Lambda_{\mathrm{b}} \rightarrow \Lambda \ell^- \bar{\nu} \mathrm{X})}}}