Light Mesons from Charm Meson Decays in FNAL E791

TL;DR

This paper analyzes charm meson decays to light mesons using Dalitz plots, revealing significant phase variation in the s-wave systems and fitting the data with resonant and non-resonant components.

Contribution

It provides the first detailed analysis of light meson structures in charm decays, identifying phase variation and fitting resonance parameters in the s-wave systems.

Findings

Significant phase variation in s-wave $K^-\pi^+$ and $\pi^-\pi^+$ systems below 1 GeV/c$^2$

Resonance parameters for $K^-\pi^+$ and $\pi^-\pi^+$ systems obtained from fits

Good fit to data achieved with resonant and non-resonant components

Abstract

An analysis of the Dalitz plots for the decays $D^+\to K^-\pi^+\pi^+$ and $D^+\to\pi^-\pi^+\pi^+$ indicates that structure with significant phase variation is required in the s-wave $K^-\pi^+$ and $\pi^-\pi^+$ systems in the region below 1 GeV/c$^2$ effective mass. A constant, non resonant "contact" term, together with a simple s-wave Breit Wigner amplitude with $M_{0}=797\pm 19\pm 43, \Gamma_{0}= 175\pm 12\pm 12$ MeV/c$^2$ for the $\Km\pip$ system and $M_{0}=478^{+24}_{-23}\pm 17, \Gamma_{0}=324^{+42}_{-40}\pm 21$ MeV/c$^2$ for the $\pi^-\pi^+$ system provide good fits to the data in this region.