# Measurement of the $e^+e^-\to K^0_{\scriptscriptstyle S}K^\pm\pi^{\mp}\pi^0$ and $K^0_{\scriptscriptstyle S}K^\pm\pi^\mp\eta$ cross sections using initial-state radiation

## TL;DR

This paper reports the first measurements of the cross sections for the processes $e^+e^- o K^0_S K^\pm \pi^\mp \pi^0$ and $e^+e^- o K^0_S K^\pm \\pi^\mp \\eta$ over energies up to 4 GeV using initial-state radiation, revealing resonance structures and $J/\psi$ decays.

## Contribution

First measurement of these specific cross sections using initial-state radiation with detailed resonance analysis and $J/\psi$ branching fractions.

## Key findings

- First cross section measurements for these processes.
- Observation of intermediate resonances like $K^{*0}$ and $K^{*}(892)^\pm$.
- Detection of $J/\psi$ in all channels with measured branching fractions.

## Abstract

The processes $e^+e^-\to K^0_{\scriptscriptstyle S}K^\pm\pi^{\mp}\pi^0$ and $e^+e^-\to K^0_{\scriptscriptstyle S}K^\pm\pi^{\mp}\eta$ are studied over a continuum of energies from threshold to 4 GeV with the initial-state photon radiation method. Using 454 fb$^{-1}$ data collected with the BABAR detector at the SLAC PEP-II storage ring, the first measurements of the cross sections for these processes are obtained. The intermediate resonance structures from $K^{*0}(K\pi)^0$, $K^{*}(892)^\pm(K\pi)^\mp$ and $K^0_{\scriptscriptstyle S}K^\pm\rho^{\mp}$ are studied. The $J/\psi$ is observed in all of these channels, and corresponding branching fractions are measured.