Observation of double charm production involving open charm in pp collisions at root s=7 TeV

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doi:10.1007/JHEP06(2012)141

The production of J/psi mesons accompanied by open charm, and of pairs of open charm hadrons are observed in pp collisions at a centre-of-mass energy of 7 TeV using an integrated luminosity of 355 pb(-1) collected with the LHCb detector. Model independent measurements of absolute cross-sections are given together with ratios to the measured J/psi and open charm cross-sections. The properties of these events are studied and compared to theoretical predictions. RI Galli, Domenico/A-1606-2012; Petrolini, Alessandro/H-3782-2011; Carbone, Angelo/C-8289-2012; de Paula, Leandro/I-9278-2012; manca, giulia/I-9264-2012; Patrignani, Claudia/C-5223-2009; Marconi, Umberto/J-2263-2012; de Simone, Patrizia/J-3549-2012; Cardini, Alessandro/J-5736-2012; Teodorescu, Eliza/K-3044-2012; Coca, Cornelia/B-6015-2012; Sarti, Alessio/I-2833-2012