A Measurement of the \(b\) and \(c\) Production Fractions with Fully Reconstructed \(D^{*+}\) Mesons in the ATLAS Detector at \(\sqrt{s}=7~\rm{TeV} \)

A measurement of the ratio of the number of \( D^{*+} \) mesons originating from a \(b\)-quark and from a directly produced charm is presented. The charm mesons are fully reconstructed in the mode \( D^{*+}\,\rightarrow\,D^{0}\pi^{+} \) where \( D^{0}\,\rightarrow\,K^{-}\pi^{+} \). The analysis is based on data collected from the minimum bias trigger of the ATLAS detector at \(\sqrt{s}=7~\rm{TeV} \) proton-proton collisions produced by the LHC. The distribution of the impact parameter of the \( D^{0} \) meson with respect to the primary vertex is studied to distinguish charm mesons produced promptly or from those through b-quark decays. The measurement of the fraction of bottom and charm quarks to the decay channel \( D^{*+}\,\rightarrow\,D^{0}\pi^{+} \), \( D^{0}\,\rightarrow\,K^{-}\pi^{+} \) applied to the total cross-section measurement of the same decay channel yields the cross-sections for direct charm and bottom production to \( D^{*+} \). I then compare the cross-section values extracted from data to NLO QCD calculations that depend on the parton distributions and fragmentation functions illuminating these Standard Model processes.