Commissioning of the PADME experiment with a positron beam

TL;DR

The PADME experiment was commissioned successfully, demonstrating its capability to detect dark photons with high sensitivity and accurately reconstruct electromagnetic processes using a positron beam at Frascati.

Contribution

This paper reports the successful commissioning of the PADME detector and details the software and calibration procedures enabling precise measurement of electromagnetic events.

Findings

Detector reaches design performance

Able to identify positron Bremsstrahlung

Capable of measuring electron-positron annihilation

Abstract

The PADME experiment is designed to search for a hypothetical dark photon $A^{\prime}$ produced in positron-electron annihilation using a bunched positron beam at the Beam Test Facility of the INFN Laboratori Nazionali di Frascati. The expected sensitivity to the $A^{\prime}$-photon mixing parameter $\epsilon$ is 10$^{-3}$, for $A^{\prime}$ mass $\le$ 23.5 MeV/$c^{2}$ after collecting $\sim 10^{13}$ positrons-on-target. This paper presents the PADME detector status after commissioning in July 2019. In addition, the software algorithms employed to reconstruct physics objects, such as photons and charged particles, and the calibration procedures adopted are illustrated in detail. The results show that the experimental apparatus reaches the design performance, and is able to identify and measure standard electromagnetic processes, such as positron Bremsstrahlung, electron-positron annihilation into two photons.