The Proton Radius Puzzle
In 2010 the proton charge radius was extracted for the first time from muonic hydrogen, a bound state of a muon and a proton. The value obtained was five standard deviations away from the regular hydrogen extraction. Taken at face value, this might be an indication of a new force in nature coupling to muons, but not to electrons. It also forces us to reexamine our understanding of the structure of the proton.
In this talk, I will describe an ongoing theoretical research effort that seeks to address this "proton radius puzzle". In particular, I will present a reevaluation of the proton structure effects, correcting 40 years of such calculations, and the development of new effective field theoretical tools that seek to directly connect muonic hydrogen and muon-proton scattering.
The Particle Physics Theory seminar is a weekly series of talks reflecting the diverse interests of the group. Topics include analytic and numerical calculations based on the Standard Model of elementary particle physics, theories exploring new physics, as well as more formal developments in gauge theories and gravity..