Study of the A dependence of the inclusive spectra of rho/sup 0/ and. omega. mesons produced by 43-GeV/c. pi. /sup -/ mesons

We report measurements of the differential cross sections dsigma/dp/sub T//sup 2/ and dsigma/dx of ..mu../sup +/..mu../sup -/ pairs from decays of rho/sup 0/ and ..omega.. mesons produced by ..pi../sup -/ mesons with momentum 43 GeV/c in beryllium and copper nuclei in the beam-fragmentation region. The shape of the spectra within the statistical accuracy does not depend on the atomic weight of the target nucleus. The exponent ..cap alpha.. of the A dependence of the cross sections, averaged over the interval x>0.6 and p/sub T//sup 2/<1.0 (GeV/c)/sup 2/, is 0.70 +- 0.05. The data obtained are compared with the results of other experiments and with theoretical models.