J/Ψ studies at the ATLAS experiment at LHC

In this document the results of the ATLAS J/Ψ studies on very early LHC proton-proton data are shown. The double differential cross-section is measured with respect to the transverse momentum and rapidity of the J/Ψ on 9.5 nb−1 of integrated luminosity. The non-prompt to prompt cross-section ratio using 17.5 nb−1 as a function of the J/Ψ transverse momentum has been estimated.