Measurements of the proton elastic-form-factor ratio mu pG p E/G p M at low momentum transfer.
PHYSICAL REVIEW LETTERS 2007;
99:202002. [PMID:
18233135 DOI:
10.1103/physrevlett.99.202002]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Indexed: 05/25/2023]
Abstract
High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected.
Collapse