First calculation of D(+) approaches (K bar)(*0)e(+)nu(sub e) in lattice QCD

The results of the calculation of the matrix elements of the quark weak current which are relevant for semileptonic decays of D-mesons into light pseudoscalar and vector mesons are presented. The computations are performed by averaging the results over 15 gauge field configurations, generated in the quenched approximation by the Metropolis algorithm, at beta = 6.0, in a 20 by 10 by 40 lattice, with Wilson fermions. From the study of matrix elements, it is found partial rate for the semileptonic decay of the D(+) into ((K bar)(sup star zero))e(+)nu(sub e) is given by gamma = (5.2 +/- 1.9)10(exp 10)/s and that the ratio of the partial rates (gamma((D(+) decays to (K(sup star zero)e(+)nu(sub e)))/(gamma((D neutral) decays to (K(-)e(+)nu(sub e)))) is given by 1.1 +/- 0.3. The ratio of the longitudinal to transverse polarization rates in (K bar)(sup star zero) decays is found to be 1.7 +/- 0.6 and is compared to experimental results. Future improvements in the accuracy of our theoretical predictions are discussed.