New high precision polarization measurements of the proton elastic form factor ratio in the Q^2 range from 0.3 to 0.7 [GeV/c]^2 have been made. These elastic H(e,e'p) measurements were done in Jefferson Lab's Hall A using 80% longitudinally polarized electrons and recoil polarimetry. For Q^2 greater than 1 [GeV/c]^2, previous polarization data indicated a strong deviation of the form factor ratio from unity which sparked renewed theoretical and experimental interest in how two-photon diagrams have been taken into account. The new high precision data indicate that the deviation from unity, while small, persists even at Q^2 less than 1 [GeV/c]^2.
@article{arxiv.1001.3341,
title = {Precision Measurements of the Proton Elastic Form Factor Ratio},
author = {D. W. Higinbotham},
journal= {arXiv preprint arXiv:1001.3341},
year = {2010}
}
Comments
5 pages, 2 figures, to appear in Proceedings of XIII International Conference on Hadron Spectroscopy (Hadron2009)