Search for the doubly charmed baryon Ξ<inf>cc</inf>⁺

A search for the doubly charmed baryon Ξ _cc ⁺ in the decay mode Ξ _cc ⁺ → Λ _c ⁺K ^-π ⁺ is performed with a data sample, corresponding to an integrated luminosity of 0.65 fb ^-1, of pp collisions recorded at a centre-of-mass energy of 7TeV. No significant signal is found in the mass range 3300-3800 MeV/c ². Upper limits at the 95% confidence level on the ratio of the Ξ _cc ⁺ production cross-section times branching fraction to that of the Λ _c ⁺, R, are given as a function of the Ξ _cc ⁺ mass and lifetime. The largest upper limits range from R < 1.5 × 10 ^-2 for a lifetime of 100 fs to R < 3.9 × 10 ^-4 for a lifetime of 400 fs. Copyright CERN.