A search for the $\it{\Xi}^{++}_{cc}$ baryon through the $\it{\Xi}^{++}_{cc} \rightarrow D^{+} p K^{} \pi^{+}$ decay is performed with a data sample corresponding to an integrated luminosity of 1.7 $\mathrm{fb}^{1}$ recorded by the LHCb experiment in $pp$ collisions at a centreofmass energy of 13 TeV. An upper limit is set on the ratio of branching fractions $\mathcal{R} = \frac{\mathcal{B}(\it{\Xi}^{++}_{cc} \rightarrow D^{+} p K^{} \pi^{+})}{\mathcal{B}(\it{\Xi}^{++}_{cc} \rightarrow \Lambda^{+}_{c} K^{} \pi^{+}\pi^{+})}$ with $\mathcal{R} < 1.7 \hspace{2pt} (2.1) \times 10^{2}$ at the 90% (95%) confidence level at the known mass of the $\it{\Xi}^{++}_{cc}$ state. No significant signal is observed in the mass range 33003800 $\mathrm{MeV}/c^{2}$.
The Feynman diagram contributing to the inclusive (left) $\Xi _{ c c }^{++}\rightarrow D ^+ p K ^ \pi ^+ $ decay with the analogous (right) $\Xi _{ c c }^{++}\rightarrow \Lambda _ c ^+ K ^ \pi ^+ \pi ^+ $ diagram. 
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Invariantmass distribution of the $ D ^+$ candidates after the analysis selection. The black points represent data. Overlaid is the fit to data which is indicated by the continuous (blue) line with the individual signal and background components of the fit represented by the dotted (red) line and dashed (green) line, respectively. 
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Invariantmass distribution of the $\Xi _{ c c }^{++}$ candidates from the (left) ${\Xi _{ c c }^{++}\rightarrow D ^+ p K ^ \pi ^+ }$ and the (right) ${\Xi _{ c c }^{++}\rightarrow \Lambda _ c ^+ K ^ \pi ^+ \pi ^+ }$ sample with the fit result overlaid. The black points represent data. In the left plot, the two vertical parallel dashed (blue) lines define the region where the signal is expected and the continuous (green) line represents the combinatorial background. In the right plot, the dashed (green) line represents combinatorial background, the dotted (red) line represents the signal contribution and the continuous (blue) line is the total fit. 
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Invariantmass distributions of rightsign (black) $ D ^+ p K ^ \pi ^+ $, wrongsignplus (red) $ D ^+ p K ^+ \pi ^+ $ and wrongsignminus (blue) $ D ^+ p K ^ \pi ^ $ data combinations are shown. The control samples have been normalised to the rightsign sample. 
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The scores from the \texttt{CLs} method for each value of the assumed ratio of branching fractions $\mathcal{R}$. Observed values are shown by the solid black line. The set upper limits at 90% and 95% CL are indicated by the dotted (blue) line and the dashed (red) line, respectively. 
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Animated gif made out of all figures. 
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Systematic uncertainties on the singleevent sensitivity $\alpha_{s}$. 
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Created on 17 August 2019.Citation count from INSPIRE on 20 August 2019.