2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/207277Studies of $D{\bar D}$ correlations for a large sample of events containing fully and partially reconstructed pairs of charmed $D$ mesons recorded by the Fermilab photoproduction experiment FOCUS (FNAL-E831) are presented. Correlations between $D$ and ${\bar D}$ mesons are used to study heavy quark production dynamics. We present results for fully and partially reconstructed charm pairs and comparisons to a recent version of \textsc{Pythia} with default parameter settings. We also comment on the production of $ψ(3770)$ in our data.14 pages, 4 figuresHigh Energy Physics - Experimenttext