Electromagnetic form factors of the pion and kaon from the instanton vacuum

Understand

We investigate the pion and kaon (pi^+, K^+, K^0) electromagnetic form factors in the space-like region: Q^2 ~< 1 GeV, based on the gauged low-energy effective chiral action from the instanton vacuum in the large N_c limit.

• Explicit flavor SU(3) symmetry breaking is taken into account.
• The nonlocal contributions turn out to be crucial to reproduce the experimental data.
• While the pion electromagnetic form factor is in good agreement with the data, the kaon one seems underestimated.