Speaker
Description
The proton radius can be determined by measuring the slope of the electric form factor at small squared four-momentum transfer $Q^2$. Numerous elastic-scattering and laser-spectroscopy measurements of the proton radius have been performed with contradicting results, the so-called proton radius puzzle. We propose to measure the proton radius in high-energy elastic muon-proton scattering at the M2 beam line of CERN's Super Proton Synchrotron in the year 2022. A high precision measurement at low $Q^2$ realized with a high-pressure hydrogen TPC can contribute to a solution of the puzzle, especially in view of the systematics of this approach compared to electron scattering. In the year 2018, a test measurement with silicon tracking detectors upstream and downstream of a prototype TPC was performed to study the feasibility employing both detector systems. We present results of the on-going analysis and discuss ideas for a possible setup in 2022.
