Exclusive production of pion and kaon meson pairs in two photon collisions at LEP

Exclusive production of π and K meson pairs in two photon collisions is measured with ALEPH data collected between 1992 and 2000. Cross-sections are presented as a function of cosθ* and invariant mass, for vertical bar cosθ* vertical bar <0.6 and invariant masses between 2.0 and 6.0 GeV/c2 (2.25 and 4.0 GeV/c2) for pions (kaons). The shape of the distributions are found to be well described by QCD predictions but the data have a significantly higher normalization