Accuracy of the pion elastic form factor extracted from a local-duality sum rule

Understand

We analyze the accuracy of the pion elastic form factor predicted by a local-duality (LD) version of dispersive sum rules.

• To probe the precision of this theoretical approach, we adopt potential models with interactions that involve both Coulomb and confining terms.
• In this case, the exact form factor may be obtained from the solution of the Schroedinger equation and confronted with the LD sum rule results.
• We use parameter values appropriate for hadron physics and observe that, independently of the details of the confining interaction, the deviation of the LD form factor from the exact form factor culminates in the region Q^2~4-6 GeV^2.