Measurement of the Total Compton Scattering Cross Section between 6.5 and 11 GeV

TL;DR

This paper reports the first measurement of the total Compton scattering cross section off electrons in the 6.5 to 11.1 GeV energy range, demonstrating high-precision experimental capabilities and comparing results with QED predictions.

Contribution

It provides the first experimental measurement of the Compton scattering cross section in this high-energy range, with improved precision and validation of QED calculations.

Findings

Total uncertainties averaged 3.4% across energy bins.

Measurement confirms QED predictions within experimental uncertainties.

Demonstrates capability for precision cross-section measurements at high energies.

Abstract

The total cross section for Compton scattering off atomic electrons, $\gamma+e\rightarrow\gamma'+e'$, was measured using photons with energies between 6.5 and 11.1 GeV incident on a $^9$Be target as part of the PrimEx-eta experiment in Hall D at Jefferson Lab. This is the first measurement of this fundamental QED process within this energy range. The total uncertainties of the cross section, combining the statistical and systematic components in quadrature, averaged to 3.4% across all energy bins. This not only demonstrates the capability of this experimental setup to perform precision cross-section measurements at forward angles but also allows us to compare with state-of-the-art QED calculations.