Precision measurement of the , , and baryon lifetimes

R Aaij, C Abellán Beteta, B Adeva, M Adinolfi… - Physical Review D, 2019 - APS
R Aaij, C Abellán Beteta, B Adeva, M Adinolfi, CA Aidala, Z Ajaltouni, S Akar, P Albicocco…
Physical Review D, 2019APS
We report measurements of the lifetimes of the Λ c+, Ξ c+ and Ξ c 0 charm baryons using
proton-proton collision data at center-of-mass energies of 7 and 8 TeV, corresponding to an
integrated luminosity of 3.0 fb-1, collected by the LHCb experiment. The charm baryons are
reconstructed through the decays Λ c+→ p K-π+, Ξ c+→ p K-π+ and Ξ c 0→ p KK-π+, and
originate from semimuonic decays of beauty baryons. The lifetimes are measured relative to
that of the D+ meson, and are determined to be τ Λ c+= 203.5±1.0±1.3±1.4 fs, τ Ξ c+ …
We report measurements of the lifetimes of the , and charm baryons using proton-proton collision data at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of , collected by the LHCb experiment. The charm baryons are reconstructed through the decays , and , and originate from semimuonic decays of beauty baryons. The lifetimes are measured relative to that of the meson, and are determined to be τΛc+=203.5±1.0±1.3±1.4  fs,  τΞc+=456.8±3.5±2.9±3.1  fs,  τΞc0=154.5±1.7±1.6±1.0  fs, where the uncertainties are statistical, systematic, and due to the uncertainty in the lifetime. The measurements are approximately 3–4 times more precise than the current world average values. The and lifetimes are in agreement with previous measurements; however, the baryon lifetime is approximately 3.3 standard deviations larger than the world average value.
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