‘‘Improved’’ lattice study of semileptonic decays ofDmesons

Abstract

We present results of a lattice computation of the matrix elements of the vector and axial-vector currents which are relevant for the semileptonic decays D -+ K and D + K*. The computations are performed in the quenched approximation to lattice QCD on a 243 x 48 lattice at = 6.2, using an O(a)-improved fermionic action. In the limit of zero lepton masses the semileptonic decays D + K and D + K* are described by four form factors: f s , V, A1, and Ap, which are functions of q 2 , where --qF is the four-momentum transferred in the process. Our results for these form factors at q 2 = 0 are f 2 ( 0 ) = 0.67' :, V(0) = 1.01?::, Al(0) = 0.70?:,, Az(0) = 0.66+:0,, which are consistent with the most recent experimental world average values. We have also determined the q2 dependence of the form factors, which we find to be reasonably well described by a simple pole-dominance model.Results for other form factors, including those relevant to the decays D -+ T and D -+ p, are also given.PACS number(s): 13.20.Fc, 12.38.G~

Lattice study of the decay model-independent determination of |Vub |

“…The extraction of the form factors from the three-point correlation function data used correlated fits [32,33]. Statistical errors are 68% confidence limits obtained from 250 bootstrap samples.…”

Heavy Quark Physics From Lattice QCD

“…For semileptonic D-meson decays the whole physical phase space can be sampled e , e In addition, one obtains the form factors for unphysical, negative, values of q 2 . Figure 6: UKQCD lattice results for the form factor f + (q 2 ) in semileptonic D → K decay 63 . The form factor is plotted as a function of the dimensionless variable q 2 a 2 and before multiplication by the appropriate lattice-to-continuum normalization factor Z eff V .…”

Study of the semileptonic decays B→π, D→π and D→K

“…. In both cases, we obtain a good description in the physical region of the experimental data [7] and previous lattice We compare with experimental data by the BES Collaboration [7] and with lattice results by the Fermilab-MILC-HPQCD [8], UKQCD [9] and APE [3] Collaborations.…”

“…results [8,9,3], without using the Omnès dispersion relation. In the case of the D → K decay, our predictions for negative q 2 values could had been improved by the Omnès representation.…”