Momentum correlations of charmed pairs produced in $\pi^{-}$-Cu interactions at 230 GeV/c

We study the production characteristics of 557 pairs of charmed hadrons produced in $\pi^{-}-$ Cu interactions at 230 GeV/c using a momentum estimator for charmed hadrons with missing decay products. We find, the mean value of the transverse momentum squared of the charmed pairs is $<p^{2}_{T, sum}>=(1.98 \pm 0.11 \pm 0.09)$; GeV$^{2}$/c$^{2}$, the mean rapidity difference is $<|y_{diff}|>=0.54 \pm 0.02 \pm 0.24$, and the mean effective mass is $<M_{eff}>=(4.45 \pm 0.03 \pm 0.13)$; GeV/c$^{2}$. Comparing these results with the next-to-leading order QCD predictions we find an agreement for the $y_{diff}$ and $M_{eff}$, whilst the measured mean value of $<p^{2}_{T, sum}>$ is significantly larger than the predicted value.