Incoherence and Multiple Parton Interactions
G. Calucci, D. Treleani
TL;DR
The paper investigates whether interference occurs between contributions to final states from different numbers of parton collisions in high-energy hadron collisions. Using a scalar, unitarity-based framework and a transverse-space analysis, it shows that when MPI are organized by topology—disconnected hard interaction regions localized in distinct transverse areas—the cross section is an incoherent sum over topologies; interference between different topologies does not modify the n-topology terms. Interference terms effectively map onto lower-topology cross sections rather than altering the higher-topology contributions. This provides a clear theoretical basis for treating MPI as independent multiple scatterings and has practical implications for modeling the underlying event and identifying multi-parton processes, including possible triple-parton scatterings, at the LHC.
Abstract
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 for the search of new physics. Different numbers of multiple collision 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.