Joint INFN-UNIMI-UNIMIB Pheno Seminars

Double parton scattering and double parton distributions - overview and recent developments

by Peter Plößl (University of Regensburg)

U3-06 (University of Milan Bicocca)


University of Milan Bicocca

Piazza della Scienza 3, 20126 Milano

Double parton scattering (DPS) describes the situation when two individual hard scattering reactions occur in a single hadron-hadron collision. In some regions of phase space DPS may give sizeable contributions to the production of multi-particle final states and thus constitutes an important background to single parton scattering (SPS) in channels suitable for the search for physics beyond the standard model. Besides this DPS is also an interesting phenomena in its own right, as it gives insight into the correlations of partons inside of hadrons.
In this talk I will review the development of a theory framework for the description of DPS, highlighting some important recent progress, and discuss in detail the double parton distributions (DPDs) containing the non-perturbative dynamics in the factorized DPS cross section. In particular I will discuss how these distributions can be defined in terms of proton matrix elements, including details about their spin and colour structure, UV renormalisation, and rapidity dependence. While DPDs are at present largely unconstrained from experimental data, they can be computed in perturbation theory for small interparton distances.
I will discuss how this is achieved at next-to-leading order and how quark mass effects can be taken into account in a consistent manner in this small distance matching.