Measurement of J/Ψ production in pp collisions at \(\sqrt{s}=7\) TeV


The production of \(J\hspace{-1.5pt}/\hspace{-0.45pt}\psi\) mesons in proton–proton collisions at \(\sqrt{s}=7\ensuremath {~\mathrm {TeV}}\) is studied with the LHCb detector at the LHC. The differential cross-section for prompt \(J\hspace{-1.5pt}/\hspace{-0.45pt}\psi\) production is measured as a function of the \(J\hspace{-1.5pt}/\hspace{-0.45pt}\psi\) transverse momentum pT and rapidity y in the fiducial region \({\ensuremath{p_{\mathrm{T}}}}\in[0;14]{\ensuremath{~\mathrm{GeV}\mskip-2mu/\mskip-1mu c}}\) and y∈[2.0;4.5]. The differential cross-section and fraction of \(J\hspace{-1.5pt}/\hspace{-0.45pt}\psi\) from b-hadron decays are also measured in the same pT and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2 pb−1. The measured cross-sections integrated over the fiducial region are for prompt \({\ensuremath{J\hspace{-1.5pt}/\hspace{-0.45pt}\psi}}\) production and for \(J\hspace{-1.5pt}/\hspace{-0.45pt}\psi\) from b-hadron decays, where the first uncertainty is statistical and the second systematic. The prompt \({\ensuremath{J\hspace{-1.5pt}/\hspace{-0.45pt}\psi}}\) production cross-section is obtained assuming no \(J\hspace{-1.5pt}/\hspace{-0.45pt}\psi\) polarisation and the third error indicates the acceptance uncertainty due to this assumption.


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