Observation of D-pi Production Correlations in 500 GeV pi- - N Interactions

We study the charge correlations between charm mesons produced in 500 GeV pi- - N interactions and the charged pions produced closest to them in phase space. With 110,000 fully reconstructed D mesons from experiment E791 at Fermilab, the correlations are studied as functions of the Dpi - D mass difference and of Feynman x. We observe significant correlations which appear to originate from a combination of sources including fragmentation dynamics, resonant decays, and charge of the beam.