Measurement of b hadron lifetimes in pp collisions at $$\sqrt{s} = 8$$s=8 $$\,\text {Te}\text {V}$$TeV

Measurements are presented of the lifetimes of the $${\mathrm {B}^0}$$ , $$\mathrm {B}^0_\mathrm {s}$$ , $$\mathrm {\Lambda }_\mathrm {b} ^0$$ , and $$\mathrm {B}_\mathrm {c}^+$$ hadrons using the decay channels $${\mathrm {B}^0}\!\rightarrow \! \mathrm {J}/\psi \mathrm {K^{*}(892)}{}^{0}$$ , $${\mathrm {B}^0}\!\rightarrow \! \mathrm {J}/\psi \mathrm {K^0_S}$$ , $$\mathrm {B}^0_\mathrm {s} \!\rightarrow \! \mathrm {J}/\psi \mathrm {\pi ^+}\mathrm {\pi ^-}$$ , $$\mathrm {B}^0_\mathrm {s} \!\rightarrow \! \mathrm {J}/\psi \mathrm {\phi (1020)}$$ , $$\varLambda _\mathrm {b}^0\!\rightarrow \!\mathrm {J}/\psi \mathrm {\Lambda }^{0}$$ , and $$\mathrm {B}_\mathrm {c}^+ \!\rightarrow \!\mathrm {J}/\psi \mathrm {\pi ^+}$$ . The data sample, corresponding to an integrated luminosity of 19.7 $$\,\text {fb}^\text {-1}$$ , was collected by the CMS detector at the LHC in proton–proton collisions at $$\sqrt{s}=8\,\text {Te}\text {V} $$ . The $${\mathrm {B}^0}$$ lifetime is measured to be $$453.0 \pm 1.6\,\text {(stat)} \pm 1.8\,\text {(syst)} \,\upmu \text {m} $$ in $$\mathrm {J}/\psi \mathrm {K^{*}(892)}{}^{0}$$ and $$457.8 \pm 2.7\,\text {(stat)} \pm 2.8\,\text {(syst)} \,\upmu \text {m} $$ in $$ \mathrm {J}/\psi \mathrm {K^0_S}$$ , which results in a combined measurement of $$c\tau _{{\mathrm {B}^0}} = 454.1 \pm 1.4\,\text {(stat)} \pm 1.7\,\text {(syst)} \,\upmu \text {m} $$ . The effective lifetime of the $$\mathrm {B}^0_\mathrm {s}$$ meson is measured in two decay modes, with contributions from different amounts of the heavy and light eigenstates. This results in two different measured lifetimes: $$c\tau _{\mathrm {B}^0_\mathrm {s} \rightarrow \mathrm {J}/\psi \mathrm {\pi ^+}\mathrm {\pi ^-}} = 502.7 \pm 10.2\,\text {(stat)} \pm 3.4\,\text {(syst)} \,\upmu \text {m} $$ and $$c\tau _{\mathrm {B}^0_\mathrm {s} \rightarrow \mathrm {J}/\psi \mathrm {\phi (1020)}} = 443.9 \pm 2.0\,\text {(stat)} \pm 1.5\,\text {(syst)} \,\upmu \text {m} $$ . The $$\mathrm {\Lambda }_\mathrm {b} ^0$$ lifetime is found to be $$442.9 \pm 8.2\,\text {(stat)} \pm 2.8\,\text {(syst)} \,\upmu \text {m} $$ . The precision from each of these channels is as good as or better than previous measurements. The $$\mathrm {B}_\mathrm {c}^+$$ lifetime, measured with respect to the $${\mathrm {B}^{+}}$$ to reduce the systematic uncertainty, is $$162.3 \pm 7.8\,\text {(stat)} \pm 4.2\,\text {(syst)} \pm 0.1\,(\tau _{{\mathrm {B}^{+}}})\,\upmu \text {m} $$ . All results are in agreement with current world-average values.