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First measurement of the lifetime of the doubly charmed baryon $\Xi_{cc}^{++}$

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Abstract

The first measurement of the lifetime of the doubly charmed baryon $\Xi_{cc}^{++}$ is presented, with the signal reconstructed in the final state $\Lambda_c^+ K^- \pi^+ \pi^+$. The data sample used corresponds to an integrated luminosity of $1.7 \mathrm{fb}^{-1}$, collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of $13\mathrm{ Te V}$. The $\Xi_{cc}^{++}$ lifetime is measured to be $0.256 ^{+0.024}_{-0.022}{ \rm (stat) } \pm 0.014 { \rm(syst)}\mathrm{ ps}$.

Figures and captions

Invariant-mass distributions of (a) $\Xi ^{++}_{ c c } \rightarrow \Lambda ^+_ c K ^- \pi ^+ \pi ^+ $ and (b) $\Lambda ^0_ b \rightarrow \Lambda ^+_ c \pi ^- \pi ^+ \pi ^- $ candidates, with fit results shown.

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Background-subtracted decay-time distributions of (dots) $\Xi ^{++}_{ c c } \rightarrow \Lambda ^+_ c K ^- \pi ^+ \pi ^+ $ and (triangles) $\Lambda ^0_ b \rightarrow \Lambda ^+_ c \pi ^- \pi ^+ \pi ^- $ candidates after the selection, not corrected for decay-time acceptance.

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Decay-time acceptances for (dots) $\Xi ^{++}_{ c c } \rightarrow \Lambda ^+_ c K ^- \pi ^+ \pi ^+ $ and (triangles) $\Lambda ^0_ b \rightarrow \Lambda ^+_ c \pi ^- \pi ^+ \pi ^- $ decays.

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Background-subtracted decay-time distribution of selected $\Xi ^{++}_{ c c } \rightarrow \Lambda ^+_ c K ^- \pi ^+ \pi ^+ $ candidates. The rate-averaged fit result across each decay-time bin is shown as the continuous line.

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Animated gif made out of all figures.

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Tables and captions

Summary of systematic uncertainties.

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tex code
Table_1.pdf

Supplementary Material [file]

Supplementary material full pdf

supple[..].pdf [128 KiB]
supplementary.pdf

This ZIP file contains supplemetary material for the publication LHCb-PAPER-2018-019. The files are: supplementary.pdf : An overview of the extra figures *.pdf, *.png, *.eps, *.C : The figures in variuous formats

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Fig1b.pdf [15 KiB]
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Created on 27 June 2020.