JLab Measurement of the $^4$He Charge Form Factor at Large Momentum Transfers
nucl-ex
/ Authors
A. Camsonne, A. T. Katramatou, M. Olson, N. Sparveris, A. Acha, K. Allada, B. D. Anderson, J. Arrington, A. Baldwin, J. -P. Chen
and 59 more authors
S. Choi, E. Chudakov, E. Cisbani, B. Craver, P. Decowski, C. Dutta, E. Folts, S. Frullani, F. Garibaldi, R. Gilman, J. Gomez, B. Hahn, J. -O. Hansen, D. Higinbotham, T. Holmstrom, J. Huang, M. Iodice, X. Jiang, A. Kelleher, E. Khrosinkova, A. Kievsky, E. Kuchina, G. Kumbartzki, B. Lee
/ Abstract
The charge form factor of $^$4He has been extracted in the range 29 fm$^{-2}$ $\le Q^2 \le 77$ fm$^{-2}$ from elastic electron scattering, detecting $^4$He nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility of Jefferson Lab. The results are in qualitative agreement with realistic meson-nucleon theoretical calculations. The data have uncovered a second diffraction minimum, which was predicted in the $Q^2$ range of this experiment, and rule out conclusively long-standing predictions of dimensional scaling of high-energy amplitudes using quark counting.