Search for paired production of D/sup 0/ and D-bar/sup 0/ mesons in. pi. /sup -/Be interactions at 55 GeV/c

The wide-aperture ''Sigma'' spectrometer was used to search for paired production of D mesons in the reaction ..pi../sup -/Be..-->..D/sup 0/D-bar/sup 0/X, with D-bar/sup 0/..-->..K/sup - +/..pi../sup + -/ and D/sup 0/..-->..K/sup - +/..pi../sup + -/. To identify the kaons, a multichannel threshold Cerenkov counter was used. In the expected region of the K..pi..-system masses, not a single event was observed. Upper bounds are estimated for the D-meson production cross section.