Heavy-to-light transition form factors and their relations in light-cone QCD sum rules

TL;DR

This paper reviews and applies an improved light-cone QCD sum rule method using chiral currents to calculate heavy-to-light transition form factors, simplifying the process and revealing natural relations among form factors.

Contribution

The paper introduces a simplified approach to compute heavy-to-light form factors using chiral currents in light-cone QCD sum rules, preserving explicit dependence on distribution amplitudes.

Findings

Relations between form factors are naturally derived.

The method reproduces known results at current accuracy.

Explicit dependence on distribution amplitudes is maintained.

Abstract

The improved light-cone QCD sum rules by using chiral current correlator is systematically reviewed and applied to the calculation of all the heavy-to-light form factors, including all the semileptonic and penguin ones. By choosing suitable chiral currents, the light-cone sum rules for all the form factors are greatly simplified and depend mainly on one leading twist distribution amplitude of the light meson. As a result, relations between these form factors arise naturally. At the considered accuracy these relations reproduce the results obtained in the literature. Moreover, since the explicit dependence on the leading twist distribution amplitudes is preserved, these relations may be more useful to simulate the experimental data and extract the information on the distribution amplitude.