First calculation of D+→anti K*0 e+νe in lattice QCD

We present the results of a 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. The computations are performed by averaging the results over 15 gauge fields configurations, generated in the quenched approximation by the Metropolis algorithm, at β=6.0, on a 20x102x40 lattice, with Wilson fermions. From the study of the matrix elements and we find that the partial rate for the semi-leptonic decay of the D+ into anti K*0e+νe is given by Γ(D+→anti K*0e+νe)=(5.2±1.9)x1010 s-1, in good agreement with the experimental result (4.1±0.7±0.5)x1010s-1, and that the ratio of the partial rates Γ(D+→anti K*0e+νe)/Γ(D0→K-e+νc) is given by 1.1±0.3, which is larger than the experimental value 0.45±0.09±0.07. We also compute the ratio of the longitudinal to transverse polarization rates in anti K*0 decays and find 1.7±0.6, to be compared to the experimental value 2.4(+1.7-0.9)±0.2. We finally discuss future improvements in the accuracy of our theoretical predictions. (orig.)