Recently an experiment at Jefferson Lab has measured the proton form factor ratio, μP GEp/GMp. down to Q2 ∼ 0.3 GeV2 with unprecedented precision. Based on the results from this experiment, a re-analysis was carried out for the world data on proton form factors, and a new result was extracted for the proton charge radius. The new result is consistent with published CODATA results and is at odds with the new muonic hydrogen measurement at PSI. We present the results of the new measurement, as well as discuss an upcoming experiment to measure the form factor ratio down to even lower Q2.
Bibliographical noteFunding Information:
This work was supported by the U.S. Department of Energy, including contract DE-AC02-06CH11357, the U.S. National Science Foundation, the Israel Science Foundation, the Korea Research Foundation, the US-Israeli Bi-National Scientific Foundation, and the Rothschild Fellowship Program of the Israel Academy of Sciences and Humanities. Jefferson Science Associates operates the Thomas Jefferson National Accelerator Facility under DOE contract DE-AC05-06OR23177.
- Form factors
- charge radius