Two-Photon Production of Lepton Pairs in Hadron-Hadron Collisions

The cross section for the two-photon exchange production of lepton pairs in hadron-hadron collisions is evaluated here up to the leading order in $\ln s$ for $s\to \infty$ holding either $M^2$ or $\frac{M^2}{s}$ fixed. To take into account elastic as well as inelastic emission of photons from hadrons, the general spectrum of equivalent photons is derived in terms of the structure functions of the hadrons and this spectrum is then used for evaluating the leading $\ln s$ terms in the two-photon cross section. The lepton mass dependence and the angular distribution of the two-photon process are also discussed.