Measurement of the Prompt J/Psi Pair Production Cross Section in pp Collisions at sqrt(s) = 8 TeV with CMS

The cross section for the prompt production of J/ψ [J/Psi] meson pairs in proton-proton√collisions at s[sqrt(s)] = 8 TeV at the LHC from a sample corresponding to an integratedluminosity of 20.2±0.5 fb−1 [inverse femtobarns] has been measured with the CMS detector.It provides unique insight into particle production and proton structure in proton-proton (pp)collisions. The two J/ψ mesons are fully reconstructed in their µ+ µ− [mu+ mu-] decay. AnJ/ψ