Experimental evidence for a light and broad scalar resonance in $D^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ decay

E791 Collaboration

From a sample of $1172\pm 61$ $D^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+}$ decay, we find $\Gamma (D^{+}\to {\pi }^{-}{\pi }^{+}{\pi }^{+})/\Gamma (D^{+}\to K^{-}{\pi }^{+}{\pi }^{+})=0.0311\pm 0.0018_{-0.0026}^{+0.0016}$. Using a coherent amp…