Seminari INFN

The proton radius puzzle and the MUSE experiment

by Michael Kohl (Hampton University e JLab)

Europe/Rome
Aula Careri (Dip. di Fisica - Edificio G. Marconi)

Aula Careri

Dip. di Fisica - Edificio G. Marconi

Description
The proton is not an elementary particle, it has a substructure governed by quarks and gluons. The spatial extensions of the electric charge and magnetization determine the size of the proton and its response to electromagnetic interaction. Recently, contradicting observations have challenged our understanding of the proton. The disagreement between proton radius determinations from high-precision muonic hydrogen spectroscopy and numerous atomic hydrogen and electron scattering measurements has become known as the proton radius puzzle, which has received much attention even in public media. The puzzle has a variety of possible resolutions, including physics beyond the Standard Model, missing conventional physics, and errors or underestimated uncertainties in the extraction of the radius from the data. I will discuss ways that will eventually help to resolve the puzzle. The MUon Scattering Experiment (MUSE) in preparation at PSI will have a key role toward a resolution of the puzzle.