A simple expression for heavy to light meson semileptonic decays form factors

Abstract

Like the two-photon and two-gluon decays of the [Formula: see text]-wave [Formula: see text] and [Formula: see text] charmonium state for which the Born term produces a very simple decays amplitude in terms of an effective Lagrangian with two-quark local operator, the Born term for the processes [Formula: see text] and [Formula: see text], could also produce the [Formula: see text] and [Formula: see text] meson semileptonic decays with the light meson [Formula: see text], [Formula: see text] in the final state. In this approach to heavy-light meson form factors with the [Formula: see text], [Formula: see text] meson treated as Goldstone boson, a simple expression is found for the decays form factors, given as: [Formula: see text], with [Formula: see text], [Formula: see text] for [Formula: see text], [Formula: see text] form factors, and [Formula: see text] for [Formula: see text], [Formula: see text] form factor. The purpose of this paper is to show that this expression for the form factors could describe rather well the [Formula: see text]-behavior observed in the BaBar, Belle and BESIII measurements and lattice simulation. In particular, the [Formula: see text] form factors are in good agreement with the measured values in the whole range of [Formula: see text] showing evidence for [Formula: see text] breaking with the presence of [Formula: see text] term in the quark propagator, but some corrections to the Born term are needed at large [Formula: see text] for [Formula: see text], [Formula: see text] form factors.