Exclusive $\pi^+$ electroproduction off the proton from low to high-$t$

Physical review / C covering nuclear physics C100(6), 065204 (2019). doi:10.1103/PhysRevC.100.065204
Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between nonperturbative and perturbative quantum chromodynamics as the square of four-momentum transfer to the struck proton, −t, is increased. Method: Cross sections for the H1(e,e′π+)n reaction were measured over the −t range of 0.272 to 2.127 GeV2 with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q2 of 2.4 GeV2, and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The −t dependence of the measured π+ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude-based theoretical model but show poor agreement with a generalized parton distribution–based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t slopes between the low- and high-−t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime.
Published by Inst., Woodbury, NY