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Measurement of the $\Omega_c^0$ baryon lifetime

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Abstract

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.

Figures and captions

Invariant-mass distributions for (left) $ D ^+ $ candidates in $B\rightarrow D ^+ \mu ^- \overline{\nu } _\mu X$ decays and (right) $\POmega ^0_ c $ candidates in $\POmega ^-_ b \rightarrow \POmega ^0_ c \mu ^- \overline{\nu } _\mu X$ decays. The results of the fits, as described in the text, are overlaid.

MassPl[..].pdf [23 KiB]
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MassPlot_DMu_rs_def_paper.pdf
MassPl[..].pdf [19 KiB]
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MassPlot_OmczMu_rs_def_paper.pdf

Decay-time spectra for (left) $ D ^+ $ signal in $B\rightarrow D ^+ \mu ^- X$ events and (right) $\POmega ^0_ c $ signal in $\POmega ^-_ b \rightarrow \POmega ^0_ c \mu ^- X$ events. Overlaid are the fit results, as described in the text, along with the uncertainties due to finite simulated sample sizes.

XcDeca[..].pdf [28 KiB]
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XcDecaytimeFit_DMu_2012_def_paper.pdf
XcDeca[..].pdf [15 KiB]
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XcDecaytimeRatioFit_OmczMu_DMu_2012_def_paper.pdf

Animated gif made out of all figures.

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Tables and captions

Summary of systematic uncertainties on the lifetime ratio, $r_{\POmega ^0_ c }$, in units of $10^{-4}$.

Table_1.pdf [60 KiB]
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tex code
Table_1.pdf

Supplementary Material [file]

Supplementary material full pdf

supple[..].pdf [92 KiB]
supplementary.pdf

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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Fig1-S.pdf [13 KiB]
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Created on 09 December 2018.Citation count from INSPIRE on 09 December 2018.