Pion and Kaon Pair Production in Photon-Photon Collisions

We report measurements of the two-photon processes e+e-→e+e-π+π- and e+e-→e+e-K+K-, at an e+e- center-of-mass energy of 29 GeV. In the π+π- data a high-statistics analysis of the f(1270) results in a γγ width Γ(γγ→f)=3.2±0.4 keV. The π+π- continuum below the f mass is well described by a QED Born approximation, whereas above the f mass it is consistent with a QCD-model calculation if a large contribution from the f is assumed. For the K+K- data we find agreement of the high-mass continuum with the QCD prediction; limits on f′(1520) and θ(1720) formation are presented.