21. March 2023

Measurement of the proton charge radius at AMBER Measurement of the proton charge radius at AMBER

Group report at DPG SMuK 2023

Author: Martin Hoffmann for the AMBER collaboration

DPG SMuK23 logo
DPG SMuK23 logo © DPG
Download all images in original size The impression in connection with the service is free, while the image specified author is mentioned.

The proton charge radius can be measured either by hydrogen spectroscopy or in lepton-proton elastic scattering. Previous measurements resulted in discrepant radii, which became known as the proton radius puzzle. The AMBER collaboration at CERN plans to perform a new precision measurement of the proton form factor at low momentum transfer using high-energy muon-proton elastic scattering. This measurement has different systematic uncertainties compared to those of low-energy elastic scattering. The recoil proton will be detected with a high-pressurized hydrogen-filled Time Projection Chamber (TPC), measuring the transferred energy and thus the squared four-momentum Q². The muon kinematics will be measured with high-precision vertex detectors around the TPC and a downstream spectrometer, which allows to select for elastic scattering events.

The core setup consisting of silicon tracking detectors and a prototype TPC was studied under realistic beam conditions during a pilot run in 2021. In 2022, the newly developed unified tracking system consisting of scintillating fibers for accurate timing and monolithic pixel-silicon detectors for high spatial precision was tested. This talk will present results of the on-going analyses and an overview of further developments towards the final setup.

Supported by EU.

Wird geladen