Study light scalar meson property from heavy meson decays

Abstract

In the SU(3) symmetry limit, the ratio $R\equiv \frac{\mathcal{B}(D^{+}\to f_0{l}^{+}\nu )+\mathcal{B}(D^{+}\to \sigma l^{+}\nu )}{\mathcal{B}(D^{+}\to a_0^0{l}^{+}\nu )}$ is equal to 1 if the scalar mesons are $\bar{q}q$ 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 $B^{-}\to S{l}^{-}\bar{\nu }$ 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.

Comments: 5 pages, talk given at 45th Rencontres de Moriond QCD and High Energy Interactions, March 2010, La Thuile and XIII International Conference on Hadron Spectroscopy, Florida, 2009