EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN) CERN-PH-EP-2013-181

Search for the doubly charmed baryon Ξ+cc The LHCb collaboration† A search for the doubly charmed baryon Ξ+cc in the decay mode Ξ cc → Λ+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/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. Published in JHEP, DOI: 10.1007/JHEP12(2013)090 c © CERN on behalf of the LHCb collaboration, license CC-BY-3.0. †Authors are listed on the following pages. ar X i