Search for the doubly charmed baryon Ξ+ cc

Abstract

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 7 TeV. No significant signal is found in the mass range 3300–3800 MeV/c2 . 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.