Study of e+e- --> Lambda anti-Lambda, Lambda anti-Sigma0, Sigma0 anti-Sigma0 using Initial State Radiation with BABAR

TL;DR

This paper reports measurements of cross sections, form factor ratios, and branching fractions for various baryon-antibaryon production processes in e+e- collisions using initial state radiation data from the BABAR experiment.

Contribution

It provides new measurements of baryon-antibaryon production cross sections, form factor ratios, and charmonium decay branching fractions at 10.58 GeV.

Findings

Cross sections for e+e- --> Lambda anti-Lambda, Lambda anti-Sigma0, Sigma0 anti-Sigma0 measured up to 3 GeV/c^2.

The ratio |G_E/G_M| for e+e- --> Lambda anti-Lambda determined.

Branching fractions for J/psi and psi(2S) decays into baryon pairs measured.

Abstract

We study the e+e- --> Lambda anti-Lambda gamma, Lambda anti-Sigma0 gamma, Sigma0 anti-Sigma0 gamma processes using 230 fb-1 of integrated luminosity collected by the BABAR detector at e+e- center-of-mass energy of 10.58 GeV. From the analysis of the baryon-antibaryon mass spectra the cross sections for e+e- --> Lambda anti-Lambda, Lambda anti-Sigma0, Sigma0 anti-Sigma0 are measured in the dibaryon mass range from threshold up to 3 GeV/c^2. The ratio of electric and magnetic form factors, |G_E/G_M|, is measured for e+e- --> Lambda anti-Lambda, and limits on the relative phase between Lambda form factors are obtained. We also measure the J/psi --> Lambda anti-Lambda, Sigma0 anti-Sigma0 and psi(2S) --> Lambda anti-Lambda branching fractions.