Search for the doubly charmed baryon $ \Xi_{cc}^{+}

A search for the doubly charmed baryon $ \Xi_{cc}^{+} $ in the decay mode $ \Xi_{cc}^{+}\to \Lambda_c^{+}{K^{-}}{\pi^{+}} $ 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 7 TeV. 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 $ \Xi_{cc}^{+} $ production cross-section times branching fraction to that of the $ \Lambda_c^{+} $ , R , are given as a function of the $ \Xi_{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.