Momentum correlations of charmed pairs produced in π−-Cu interactions at 230 GeV/c

We study the production characteristics of 557 pairs of charmed hadrons produced in π−-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 〈pT, sum2〉 = (1.98 ± 0.11 ± 0.09) GeV2/c2, the mean rapidity difference is 〈 |ydiff| 〉 = 0.54 ± 0.02 ± 0.24, and the mean effective mass is 〈Meff〉 = (4.45 ± 0.03 ± 0.13) GeV/c2. Comparing these results with the next-to-leading order QCD predictions we find an agreement for ydiff and Meff, whilst the measured mean value of pT, sum2 is significantly larger than the predicted value.