Incoherence and multiple parton interactions

At the LHC multiple parton interactions will represent an important feature of the minimum bias and of the underlying event, and will give important contributions in many channels of interest in the search for new physics. Different numbers of multiple collisions may contribute to the production of a given final state, and one should expect important interference effects in the regime where different contributions have similar rates. We show, on the contrary, that, once multiple parton interactions are identified by their different topologies, terms with different numbers of multiple parton interactions do not interfere in the final cross section.