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The central exclusive production (CEP) of heavy resonance states thatsubsequently decay into meson pairs, MMbar, is an important signature for suchprocesses at hadron colliders. However there is a potentially importantbackground from the direct QCD production of meson pairs, as mediated forexample by the exclusive gg --> MMbar hard scattering subprocess. This is infact an interesting process in its own right, testing novel aspects ofperturbative QCD technology. We explicitly calculate the gg --> MMbar helicityamplitudes for different meson states within the hard exclusive formalism, andcomment on the application of MHV techniques to the calculation. Using theseresults, we describe how meson pair CEP can be calculated in the perturbativeregime, and present some sample numerical predictions for a variety of finalstates. We also briefly consider the dominant non-perturbative contributions,which are expected to be important when the meson transverse momentum is small.

Central exclusive meson pair production in the perturbative regime at hadron colliders