Search for the doubly charmed baryon Ξ_cc⁺

A search for the doubly charmed baryon $\Xi_{cc}^+$ is performed through its decay to the $\Lambda_c^ + {K^ -}{\pi ^ +}$ final state, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. The data correspond to a total integrated luminosity of 9 fb$^{−1}$. No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c$^{2}$. Upper limits are set at 95% credibility level on the ratio of the $\Xi_{cc}^+$ production cross-section times the branching fraction to that of $\Lambda_c^ + $ and $\Xi_{cc}^{+ +}$ baryons. The limits are determined as functions of the $\Xi_{cc}^+$ mass for different lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.