MUSE Introduces Advanced Beamline Calorimeter for Precision Measurements

The MUon Scattering Experiment (MUSE) has introduced a new beamline calorimeter designed to address several significant physics goals. The experiment is primarily motivated by the proton radius puzzle, which highlights discrepancies between measurements obtained from muonic hydrogen spectroscopy and those from electron-proton interactions. MUSE aims to test lepton universality, measure two-photon exchange contributions, and evaluate radiative corrections.

To achieve these objectives, MUSE employs a mixed-species beam to simultaneously measure high-precision cross sections for both electron-proton and muon-proton scattering. The experiment will operate with both positive and negative beam polarities. A key component of this setup is the lead-glass calorimeter, which has been installed at the end of the beam line to facilitate precise cross-section measurements. Understanding the incident beam energy and the necessary radiative corrections is crucial for accurate results.

The paper discusses the specifications, calibration, and performance of the calorimeter, demonstrating that its performance aligns well with simulation predictions and meets the experimental requirements. This advancement in detector technology is expected to enhance the precision of measurements in particle physics, contributing to a deeper understanding of fundamental interactions.

The findings are detailed in the paper titled "The MUSE Beamline Calorimeter" authored by W. Lin and 42 co-authors, available on arXiv: arXiv:2408.13380.