Measurement of $\phi$(1020) meson leptonic width with CMD-2 detector at VEPP-2M Collider

TL;DR

This paper reports a precise measurement of the $$ meson's leptonic width and decay branching ratios using data from the CMD-2 detector at VEPP-2M, refining key parameters of this meson.

Contribution

The study provides the first combined analysis of four major decay modes of the $$ meson to determine its leptonic width with high precision.

Findings

Measured $$ leptonic width as 1.235 keV with uncertainties.

Recalculated branching ratios for four main decay channels.

Improved accuracy of $$ meson parameters.

Abstract

The $\phi$(1020) meson leptonic width has been determined from the combined analysis of 4 major decay modes of the resonance ($\phi\to K^+ K^-,K^0_LK^0_S,\pi^+\pi^-\pi^0,\eta\gamma$) studied with the CMD-2 detector at the VEPP-2M $e^+e^-$ collider. The following value has been obtained: $\Gamma(\phi\to e^+e^-) = 1.235\pm 0.006\pm 0.022$ keV. The $\phi(1020)$ meson parameters in four main decay channels have been also recalculated: $B(\phi\to K^+K^-) = 0.493\pm 0.003\pm 0.007$, $B(\phi\to K_LK_S) = 0.336\pm 0.002\pm 0.006$, $B(\phi\to\pi^+\pi^-\pi^0) = 0.155\pm 0.002\pm 0.005$, $B(\phi\to\eta\gamma) = 0.0138\pm 0.0002\pm 0.0002$.