Measurements of the parameters of the $\phi(1020)$ resonance through studies of the processes $e^+e^- \to K^+K^-$, $K_SK_L$ and $\pi^+\pi^-\pi^0$

TL;DR

This study measured the parameters of the $\,phi(1020)$ resonance through detailed analysis of cross sections in specific $e^+e^-$ annihilation processes near the resonance energy, providing updated resonance characteristics.

Contribution

The paper presents new measurements of the $\,phi(1020)$ resonance parameters using a large dataset and analyzes the results within the vector meson dominance model, revealing deviations in the $\, ext{width}$ and additional contributions in certain decay channels.

Findings

Measured $\, ext{width}$ of $\, ext{phi}$ meson is lower than the world average.

Determined main decay modes and their branching ratios.

Found additional contributions beyond the conventional model in the $e^+e^- o \, ext{pi}^+ ext{pi}^- ext{pi}^0$ process.

Abstract

The cross sections of the processes $e^+e^- \to K^+K^-$, $e^+e^- \to K_SK_L$ and $e^+e^- \to \pi^+\pi^-\pi^0$ were measured in the SND experiment at the VEPP-2M collider in the energy region near the $\phi(1020)$ meson. These measurements were based on about $10^6$ $K^+K^-$, $0.5 \times 10^6$ $K_SK_L$ and $0.4 \times 10^6$ $\pi^+\pi^-\pi^0$ selected events. Themeasured cross sections have been analyzed in the framework of the vector meson dominance model and the main parameters of the $\phi$-resonance were obtained, such as its mass, width, the production cross section and branching ratios of the main decay modes. The measured value of the $\phi$ meson total width, $\Gamma_{\phi} = 4.21 \pm 0.04$ is lower than the present world average of $4.458 \pm 0.032$ MeV. Contributions in addition to the conventional vector meson dominance model were found in the $e^+e^- \to \pi^+\pi^-\pi^0$ reaction cross section.