Speaker
Description
We study the $D^+_s \to \pi^+ \pi^+ \pi^-$ and $D^+_s \to \pi^+ K^+ K^-$ decays adopting a mechanism in which the $D^+_s$ decays weakly into a $\pi^+$ and a $q\bar{q}$ component, which hadronizes into two pseudoscalar mesons. The final state interactions between these two pseudoscalar mesons is taken into account by using a chiral unitary approach in coupled channels, which gives rise to the $f_0(980)$ resonance. Hence, we obtain the invariant mass distribution of the pairs $\pi^+\pi^-$ and $K^+K^-$ after the decay of that resonance and compare our theoretical amplitudes with those available from the experimental data. Our results are in a fair agreement with the shape of these data, within large uncertainty, and a $f_0(980)$ signal is seen in both the $\pi^+\pi^-$ and $K^+K^-$ distributions. Predictions for the relative size of $\pi^+\pi^-$ and $K^+K^-$ distributions are made.
