Coupled channel analysis of $\pi^+ \pi^ -\pi^0$, $K^+ K^- \pi^0$ and $K^{\pm} K^0_S \pi^{\mp}$ from $\bar p p$ annihilation at rest in hydrogen targets at three densities

Abstract.

The $\pi^+ \pi^ -\pi^0$, $K^+ K^- \pi^0$ and $K^\pm K^0 \pi^\mp$ final states produced by $\bar p p$ annihilation at rest at three different hydrogen target densities have been analyzed in the frame of a coupled channel analysis together with $\pi \pi$, $\pi K$ and $K \bar K$ scattering data. The percentages of the different partial waves, the branching ratios and the parameters (masses, widths, $\pi \pi$ and $K \bar K$ partial widths) of all the involved resonances (J ^P = 0⁺, 1^-, 2⁺) have been measured. The main results on meson spectroscopy concern the determination of the $\Gamma_{K \bar K}/\Gamma_{\pi \pi}$ ratio for f ₀ (1370) and f ₀ (1500) ($\Gamma_{K \bar K}/\Gamma_{\pi \pi} = 0.91 \pm 0.2 0$ and $\Gamma_{K \bar K}/\Gamma_{\pi \pi} = 0.25 \pm 0.03$ respectively), the determination of a ₀ (1300) parameters ($M=1303 \pm 16$MeV; $\Gamma= 92 \pm 16$MeV) and the observation of two different $\rho$ signals associated to $\rho(1450)$ and $\rho(1700)$ ($M=1182 \pm 30$MeV;$\Gamma=389 \pm 20$MeV and $M=1594 \pm 20$MeV;$\Gamma=259 \pm 20$MeV respectively).