## Abstract

We study the pion electromagnetic half-off-shell form factors F_{1} and F_{2} using an exactly solvable manifestly covariant model of a (3 + 1) dimensional fermion field theory. The model provides a three-dimensional imaging of F_{1} and F_{2} as a function of (Q^{2},t), which are constrained by the Ward-Takahashi identity. The normalization of the charge form factor F_{1} is fixed by F_{1}(Q^{2} = 0,t = m^{2}_{π}) = 1 while the other form factor F_{2} vanishes, i.e. F_{2}(Q^{2},t = m^{2}_{π}) = 0 for any value of Q^{2} due to the time-reversal invariance of the strong interaction. The new form factor defined by g(Q^{2},t) = F_{2}(Q^{2},t)/(t − m^{2}_{π}) is however measurable in the on-mass-shell limit. We note that g(Q^{2} = 0,t = m^{2}_{π}) is related with the pion charge radius.

Original language | English |
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Journal | Proceedings of Science |

Volume | 374 |

State | Published - 2019 |

Event | 2019 Light Cone - QCD on the Light Cone: From Hadrons to Heavy Ions, LC 2019 - Palaiseau, France Duration: 16 Sep 2019 → 19 Sep 2019 |