Precision measurement of the ${\mathrm{\Xi }}_{cc}^{++}$ mass

A measurement of the ${\mathrm{\Xi }}_{cc}^{++}$ mass is performed using data collected by the LHCb experiment between 2016 and 2018 in $pp$ collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.6 ${\mathrm{f}\mathrm{b}}^{-1}$. The ${\mathrm{\Xi }}_{cc}^{++}$ candidates are reconstructed via the decay modes ${\mathrm{\Xi }}_{cc}^{++}\to {\mathrm{\Lambda }}_c^{+}{K}^{-}{\pi }^{+}{\pi }^{+}$ and ${\mathrm{\Xi }}_{cc}^{++}\to {\mathrm{\Xi }}_c^{+}{\pi }^{+}$. The result, $3621.55 \pm 0.23{\rm,(stat),} \pm 0.30 {\rm,(syst),}{\rm MeV}/c^2$,isthemostprecisemeasurementofthe$\Xi_{cc}^{++}$ mass to date.