Measurements of the observed cross sections for $e^+e^-\to$ exclusive light hadrons containing $\pi^0\pi^0$ at $\sqrt s= 3.773$, 3.650 and 3.6648 GeV

TL;DR

This study measures the cross sections of specific light hadron final states in electron-positron collisions at three energies, providing insights into $ ext{psi}(3770)$ decay modes and setting upper limits on their branching fractions.

Contribution

It provides the first measurements of these exclusive light hadron cross sections at these energies and constrains $ ext{psi}(3770)$ decay channels.

Findings

Measured cross sections for multiple light hadron final states.

Set upper limits on $ ext{psi}(3770)$ decay branching fractions.

Provided data for understanding charmonium decay mechanisms.

Abstract

By analyzing the data sets of 17.3, 6.5 and 1.0 pb$^{-1}$ taken, respectively, at $\sqrt s= 3.773$, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for $e^+e^-\to \pi^+\pi^-\pi^0\pi^0$, $K^+K^-\pi^0\pi^0$, $2(\pi^+\pi^-\pi^0)$, $K^+K^-\pi^+\pi^-\pi^0\pi^0$ and $3(\pi^+\pi^-)\pi^0\pi^0$ at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for $\psi(3770)$ decay into these final states at 90% C.L..