Motivations The production mechanism in pp collisions still unclear Several models around : Color singlet and color octet mechanisms (NRQCD) describe the p T spectrum and cross section of the J/ as measured by Tevatron, but not the polarization (and has other failures) Other models such as color evaporation model, kt factorization, soft color interaction model cannot describe the data either New data from LHC experiments will help to resolve this issue 4.10.2010Giulia Manca7 J/ cross section crucial milestone in understanding detector and first step to B cross section measurement
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