We report a measurement of the lifetime of the $\Omega_c^0$ baryon 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 sample consists of about 1000 $\Omega_b^-\to\Omega_c^0\mu^-\bar{\nu}_{\mu} X$ signal decays, where the $\Omega_c^0$ baryon is detected in the $pK^-K^-\pi^+$ final state and $X$ represents possible additional undetected particles in the decay. The $\Omega_c^0$ lifetime is measured to be $\tau_{\Omega_c^0} = 268\pm24\pm10\pm2$ fs, where the uncertainties are statistical, systematic, and from the uncertainty in the $D^+$ lifetime, respectively. This value is nearly four times larger than, and inconsistent with, the current world-average value.
Invariant-mass distributions for (left) $ D ^+ $ candidates in $B\rightarrow D ^+ \mu ^- \overline{\nu } _\mu X$ decays and (right) $\Omega ^0_ c $ candidates in $\Omega ^-_ b \rightarrow \Omega ^0_ c \mu ^- \overline{\nu } _\mu X$ decays. The results of the fits, as described in the text, are overlaid. |
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Decay-time spectra for (left) $ D ^+ $ signal in $B\rightarrow D ^+ \mu ^- X$ events and (right) $\Omega ^0_ c $ signal in $\Omega ^-_ b \rightarrow \Omega ^0_ c \mu ^- X$ events. Overlaid are the fit results, as described in the text, along with the uncertainties due to finite simulated sample sizes. |
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Animated gif made out of all figures. |
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Summary of systematic uncertainties on the lifetime ratio, $r_{\Omega ^0_ c }$, in units of $10^{-4}$. |
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Supplementary material full pdf |
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This ZIP file contains supplemetary material for the publication LHCb-PAPER-2018-028. The files are: Supplementary.pdf : An overview of the extra figures *.pdf, *.png, *.eps : The figures in variuous formats |
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Created on 27 April 2024.