Kl3 and pion form factors using partially twisted boundary conditions

We compute the Kl3 and pion form factors using partially twisted boundary conditions. The twists are chosen so that the Kl3 form factors are calculated directly at zero momentum transfer (q^2=0), removing the need for a q^2 interpolation, while the pion form factor is determined at values of q^2 close to q^2=0. The simulations are performed on an ensemble of the RBC/UKQCD collaboration's gauge configurations with Domain Wall Fermions and the Iwaski gauge action with an inverse lattice spacing of 1.73(3) GeV. Simulating at a single pion mass of 330 MeV, we find the pion charge radius to be _{330 MeV}=0.354(31) fm^2 which, using NLO SU(2) chiral perturbation theory, translates to a value of =…