Transition form factors for $D/B$ to $a_{0}(980)$ from light-cone QCD sum rules

TL;DR

This paper calculates transition form factors for $D/B$ to $a_{0}(980)$ decays using light-cone QCD sum rules, considering both two-quark and tetraquark components, and compares results with experimental data.

Contribution

It introduces a method to include tetraquark components in form factor calculations for $D/B$ to $a_{0}(980)$ decays within light-cone QCD sum rules.

Findings

Branching fractions align with experimental data when tetraquark components are included.

Form factors are computed free of twist-three distribution amplitude contributions.

Derived relations connect different form factors for the decay processes.

Abstract

We apply the light-cone QCD sum rules with chiral currents to compute transition form factors of the semileptonic decay of the charmed and bottom scalar mesons $D/B$ to $a_{0}(980)l^{+}\nu_{l}$ $(l=e$, $\mu)$, where the scalar meson $a_{0}(980)$ are firstly regarded as two quark states, and contributions from the tetraquark component are then added via proper modulation of four distribution amplitudes considered. The obtained transition form factors and branching fraction are free of the contribution from the light-cone distribution amplitudes at the level of twist-three and two simple relations connecting their form factors are obtained. Our computations indicates that the decay branch fractions are on the margin of the measurements reported by Beijing Spectrometer \uppercase\expandafter{\romannumeral3} in the pure two-quark scenario and are in good agreement with observations when tetraquark component is considered.