Helicity form factors for D_{(s)} rightarrow A ell nu process in the light-cone QCD sum rules approach

Abstract

The helicity form factors of the D_{(s)}rightarrow A ell ^+ nu with A=a_{1}^{-}, a_{1}^{0}, b_{1}^{-}, b_{1}^{0}, K_{1}(1270) and K_{1}(1400) are calculated in the light-cone sum rules approach, up to twist-3 distribution amplitudes of the axial vector meson A. In the helicity form factors parametrization the unitarity constraints are applied to the fitting parameters. In addition, the effects of the low-lying resonances are included in series expansions of aforementioned form factors. The properties of the D_{(s)}rightarrow A ell ^+ nu semileptonic decays are studied by extending the form factors to the whole physical region of q^2. For a better analysis, a comparison is also made between our results and the predictions obtained using transition form factors via LCSR, 3PSR and CLFQM methods.