Characterization of the PADME positron beam for the X17 measurement

TL;DR

This paper details the precise characterization of the PADME positron beam, including measurements of its position, momentum, energy spread, and intensity, crucial for the X17 measurement experiment.

Contribution

It introduces a comprehensive methodology combining data analysis and simulations to accurately measure key beam parameters for the PADME experiment.

Findings

Beam momentum measured with 1-2 MeV/c precision

Energy spread below 0.25%

Beam intensity known within 2% accuracy

Abstract

This paper presents a detailed characterization of the positron beam delivered by the Beam Test Facility at Laboratori Nazionali of Frascati to the PADME experiment during Run III, which took place from October to December 2022. It showcases the methodology used to measure the main beam parameters such as the position in space, the absolute momentum scale, the beam energy spread, and its intensity through a combination of data analysis and Monte Carlo simulations. The results achieved include an absolute precision in the momentum of the beam to within $\sim$ 1-2 MeV$/c$, a relative beam energy spread below 0.25\%, and an absolute precision in the intensity of the beam at the level of 2\% percent.