Measurements of the B+, B0, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ B_s^0 $\end{document} meson and \documentc

Measurements of b-hadron lifetimes are reported using pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected by the LHCb detector at a centre-of-mass energy of 7 TeV. Using the exclusive decays B+ → J/ψK+, B0 → J/ψK∗(892)0, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ {B^0}\to {J \left/ {{\psi K_s^0}} \right.} $\end{document}, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ \Lambda_b^0\to {J \left/ {{\psi \varLambda }} \right.} $\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ B_s^0\to {J \left/ {{\psi \phi }} \right.} $\end{document} the average decay times in these modes are measured to be \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ \begin{array}{*{20}{c}} {{\tau_{{{B^{+}}\to {J \left/ {{\psi {K^{+}}}} \right.}}}}=1.637\pm 0.004\pm 0.003ps,} \\ {{\tau_{{{B^0}\to {J \left/ {{\psi {K^{*0 }}}} \right.}}}}=1.524\pm 0.006\pm 0.004ps,} \\ {{\tau_{{{B^0}\to {J \left/ {{\psi K_s^0}} \right.}}}}=1.499\pm 0.013\pm 0.005ps,} \\ {{\tau_{{\Lambda_b^0\to {J \left/ {{\psi \varLambda }} \right.}}}}=1.415\pm 0.027\pm 0.006ps,} \\ {{\tau_{{B_s^0\to {J \left/ {{\psi \phi }} \right.}}}}=1.480\pm 0.011\pm 0.005ps,} \\ \end{array} $\end{document}where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, ΔΓd, to the average width, Γd, in the B0 system, ΔΓd/Γd = −0.044 ± 0.025 ± 0.011, are reported. All quantities are found to be consistent with Standard Model expectations.