φK+K- production in electron-positron annihilation

In this work we study the e+e-→φK+K- reaction. The leading order electromagnetic contributions to this process involve the γ*φK+K- vertex function with a highly virtual photon. We calculate this function at low energies using RχPT supplemented with the anomalous term for the VV'P interactions. Tree-level contributions involve the kaon form factors and the K*K transition form factors. We improve this result, valid for low photon virtualities, replacing the lowest order terms in the kaon form factors and K*K transition form factors by the form factors as obtained in UχPT in the former case and the ones extracted from recent data on e+e-→KK* in the latter case. We calculate rescattering effects which involve meson-meson amplitudes. The corresponding result is improved using the unitarized meson-meson amplitudes containing the scalar poles instead of the lowest order terms. Using the BABAR value for BR(X→φf0)Γ(X→e+e-), we calculate the contribution from intermediate X(2175). A good description of data is obtained in the case of destructive interference between this contribution and the previous ones, but more accurate data on the isovector K*K transition form factor is required in order to exclude contributions from an intermediate isovector resonance to e+e-→φK+K- around 2.2 GeV.