Study light scalar meson property from heavy meson decays

TL;DR

This paper proposes a model-independent method using decay ratios in heavy meson decays to distinguish whether light scalar mesons are quark-antiquark pairs or tetraquarks, with potential for experimental verification.

Contribution

It introduces a ratio-based approach to identify the internal structure of light scalar mesons, applicable across different heavy meson decay processes, and discusses the effects of SU(3) symmetry breaking.

Findings

The ratio R equals 1 for $ar qq$ states and 3 for tetraquark states.

Branching fractions are estimated as $10^{-4}$, $10^{-5}$, and $10^{-6}$ for different decay channels.

The method is feasible with current and upcoming experimental facilities.

Abstract

In the SU(3) symmetry limit, the ratio $R\equiv\frac{{\cal B}(D^+\to f_0l^+\nu)+ {\cal B}(D^+\to \sigma l^+\nu)}{{\cal B}(D^+\to a_0^0l^+\nu)}$ is equal to 1 if the scalar mesons are $\bar qq$ states, while it is 3 if these mesons are tentraquark states. This ratio provides a model-independent way to distinguish the descriptions for light scalar mesons . It also applies to the $B^-\to Sl^-\bar\nu$ and $\bar B^0\to J/\psi(\eta_c) S$ decays. The SU(3) symmetry breaking effect is found to be under control, which will not spoil our method. The branching fractions of the $D^+\to S l^+\nu$, $B^-\to S l^-\bar\nu$ and $\bar B^0\to J/\psi(\eta_c) S$ decays roughly have the order $10^{-4}$, $10^{-5}$ and $10^{-6}$, respectively. The B factory experiments and ongoing BEPC-II experiments are able to measure these channels and accordingly to provide the detailed information of the scalar meson inner structure.