Pion Electromagnetic Form Factor at Spacelike Momenta

L. Chang, I. C. Cloët, C. D. Roberts, S. M. Schmidt, and P. C. Tandy
Phys. Rev. Lett. 111, 141802 – Published 1 October 2013

Abstract

A novel method is employed to compute the pion electromagnetic form factor, Fπ(Q2), on the entire domain of spacelike momentum transfer using the Dyson-Schwinger equation (DSE) framework in QCD. The DSE architecture unifies this prediction with that of the pion’s valence-quark parton distribution amplitude (PDA). Using this PDA, the leading-order, leading-twist perturbative QCD result for Q2Fπ(Q2) underestimates the full computation by just 15% on Q28GeV2, in stark contrast to the result obtained using the asymptotic PDA. The analysis shows that hard contributions to the pion form factor dominate for Q28GeV2, but, even so, the magnitude of Q2Fπ(Q2) reflects the scale of dynamical chiral symmetry breaking, a pivotal emergent phenomenon in the standard model.

  • Figure
  • Figure
  • Received 1 July 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.141802

© 2013 American Physical Society

Authors & Affiliations

L. Chang1, I. C. Cloët2, C. D. Roberts2, S. M. Schmidt3, and P. C. Tandy4

  • 1Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich, Germany
  • 2Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
  • 3Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany
  • 4Center for Nuclear Research, Department of Physics, Kent State University, Kent, Ohio 44242, USA

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Vol. 111, Iss. 14 — 4 October 2013

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