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

Exclusive production of $\pi$ 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 \cos\theta^* and invariant mass, for |\cos\theta^* |< 0.6 and invariant masses between 2.0 and 6.0 \mathrm{GeV}/c^2 (2.25 and 4.0 \mathrm{GeV}/c^2) for pions (kaons). The shape of the distributions are found to be well described by QCD predictions but the data have a significantly higher normalisation