The ratio of the Λb0 baryon lifetime to that of the B ̄0 meson is measured using 1.0 fb -1 of integrated luminosity in 7 TeV center-of-mass energy pp collisions at the LHC. The Λb0 baryon is observed for the first time in the decay mode Λb0→J/ψpK -, while the B ̄0 meson decay used is the well known B ̄0→J/ψπ +K - mode, where the π +K - mass is consistent with that of the K ̄*0(892) meson. The ratio of lifetimes is measured to be 0.976±0.012±0.006, in agreement with theoretical expectations based on the heavy quark expansion. Using previous determinations of the B ̄0 meson lifetime, the Λb0 lifetime is found to be 1.482±0.018±0.012 ps. In both cases, the first uncertainty is statistical and the second systematic.
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)