Abstract:
The AMBER collaboration plans to perform a new precision measurement of the proton electric form factor at low squared four-momentum transfers (Q2) by elastic scattering of high-energy muons off protons. This experiment features a high-intensity 100 GeV muon beam at the M2 beam line of CERN’s Super Proton Synchrotron, leading to reduced and different systematic uncertainties compared to low-energy lepton-proton elastic scattering experiments. A high-pressure hydrogen-filled Time Projection Chamber (TPC) serves as an active target and measures the energy transferred to the recoil proton. The muon trajectories and momenta are reconstructed by high-precision vertex detectors surrounding the TPC and a magnetic spectrometer. In this way, the measurement is over-constrained to cleanly select elastic scattering events.
In 2021, the core setup was studied under realistic beam conditions in a pilot run utilizing a prototype TPC and silicon strip detectors. Prototypes of the required tracking detectors and a free-running data acquisition were tested in 2022 and 2023. This talk will present ongoing analyses and an overview of further developments towards the main experiment.
Supported by EU.