Proton charge radius extraction from electron scattering data using dispersively improved chiral effective field theory

Alarcón, J.M. (Departamento de Física Teórica, Universidad Complutense de Madrid, 28040 Madrid, Spain) ; Higinbotham, D.W. (Jefferson Lab, Newport News, Virginia 23606, USA) ; Weiss, C. (Jefferson Lab, Newport News, Virginia 23606, USA) ; Ye, Zhihong (Argonne National Laboratory, Argonne, Illinois 60439, USA)

09 April 2019

Abstract: We extract the proton charge radius from the elastic form factor (FF) data using a novel theoretical framework combining chiral effective field theory and dispersion analysis. Complex analyticity in the momentum transfer correlates the behavior of the spacelike FF at finite Q2 with the derivative at Q2=0. The FF calculated in the predictive theory contains the radius as a free parameter. We determine its value by comparing the predictions with a descriptive global fit of the spacelike FF data, taking into account the theoretical and experimental uncertainties. Our method allows us to use the finite-Q2 FF data for constraining the radius (up to Q20.5 GeV2 and larger) and avoids the difficulties arising in methods relying on the Q20 extrapolation. We obtain a radius of 0.844(7) fm, consistent with the high-precision muonic hydrogen results.

Published in: Physical Review C 99 (2019)
Published by: APS
DOI: 10.1103/PhysRevC.99.044303
arXiv: 1809.06373
License: CC-BY-4.0

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