Chiral and volume extrapolation of pion and kaon electromagnetic form factor within SU(3) ChPT

We calculate the pion and kaon electromagnetic form factors in finite volume for a generic momentum transfer in space-like region, using SU(3) chiral perturbation theory. To this end, we first find the hadronic matrix element in a new form which is suitable for our calculation in finite volume. We present our numerical findings for the chiral behavior and finite volume corrections and compare these for pion and kaon form factors. As a result, for the pion electromagnetic form factor we find the finite volume correction $\Delta F^{\pi}_{em} = 0.0041$ at momentum transfer $q^2 = -0.1358$ and for the kaon form factor $\Delta F^{K}_{em} = 0.0029$ at $q^2 = -0.1357$ with $m_{\pi} = 0.3128$ and $L = 2.6 fm$ as the linear size of the lattice.