Measurement of the lifetime of the doubly charmed baryon ${\mathrm{\Xi }}_{cc}^{++}$

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