Measurement of b hadron lifetimes in pp collisions at $$\sqrt{s} = 8$$ $$\,\text {Te}\text {V}$$
Here, measurements are presented of the lifetimes of the B$^0$, B$$^0_\mathrm{s}$$, $$\Lambda^0_\mathrm{b}$$, and B$$_\mathrm{c}^+$$ hadrons using the decay channels B$$^0\to$$J/$$\psi$$K*(892)$^0$, B$$^0\to$$J/$$\psi$$K$$^0_\mathrm{S}$$, B$$^0_\mathrm{s}\to$$J/$$\psi \pi^+\pi^-$$, B$$^0_\mathrm{s}\to$$J/$$\psi\phi$$(1020), $$\Lambda^0_\mathrm{b}\to$$J/$$\psi\Lambda^0$$, and B$$_\mathrm{c}\to$$J/$$\psi\pi^+$$. The data sample, corresponding to an integrated luminosity of 19.7 fb$$^{-1}$$, was collected by the CMS detector at the LHC in proton-proton collisions at $$\sqrt{s}=$$ 8 TeV. The B$^0$ lifetime is measured to be 453.0 $$\pm$$ 1.6 (stat) $$\pm$$ 1.8 (syst) $$\mu$$m in J/$$\psi$$K*(892)$^0$ and 457.8 $$\pm$$ 2.7 (stat) $$\pm$$ 2.8 (syst) $$\mu$$m in J/$$\psi$$K$$^0_\mathrm{S}$$, which results in a combined measurement of $$c\tau_{\mathrm{B}^0} = $$454.1 $$\pm$$ 1.4 (stat) $$\pm$$ 1.7 (syst) $$\mu$$m. The effective lifetime of the 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: $$c\tau_{\mathrm{B}^0_\mathrm{s} \to \mathrm{J}/\psi \pi^+\pi^-} =$$ 502.7 $$\pm$$ 10.2 (stat) $$\pm$$ 3.4 (syst) $$\mu$$m and $$c\tau_{\mathrm{B}^0_\mathrm{s} \to \mathrm{J}/\psi\phi(1020)} = $$443.9 $$\pm$$ 2.0 (stat) $$\pm$$ 1.5 (syst) $$\mu$$m. The $$\Lambda^0_\mathrm{b}$$ lifetime is found to be 442.9 $$\pm$$ 8.2 (stat) $$\pm$$ 2.8 (syst) $$\mu$$m. The precision from each of these channels is as good as or better than previous measurements. The B$$_\mathrm{c}^+$$ lifetime, measured with respect to the B$^+$ to reduce the systematic uncertainty, is 162.3 $$\pm$$ 7.8 (stat) $$\pm$$ 4.2 (syst) $$\pm$$ 0.1 $$(\tau_{\mathrm{B}^+})$$ $$\mu$$m. All results are in agreement with current world-average values.
- Research Organization:
- Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- Contributing Organization:
- CMS Collaboration
- Grant/Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1409381
- Report Number(s):
- FERMILAB-PUB-17-540-CMS; CMS-BPH-13-008; CERN-EP-2017-244; arXiv:1710.08949; 1632444
- Journal Information:
- European Physical Journal. C, Particles and Fields, Vol. 78, Issue 6; ISSN 1434-6044
- Publisher:
- SpringerCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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