The structure of hadrons (protons) and the dynamics of their interaction are usually studied in collisional experiments by exploring hard single parton–parton scattering described in terms of structure functions (single-particle distributions). Completely new and unique information comes from the selection and analysis of events in which two (or more) hard parton scatterings concurrently occur in a single (Tevatron; FermiLab, USA) or pp (LHC; CERN, Switzerland) collision. The simulation of such double (multiple) parton scatterings involves two-parton (multiparton) distribution functions. Properties of these functions, which may be extracted from quantum chromodynamics, are reviewed.

强子（质子）的结构及其相互作用的动力学通常在碰撞实验中通过探索用结构函数（单粒子分布）描述的硬单子-子散射来研究。全新且独特的信息来自对在单次（Tevatron；费米实验室，美国）或 pp（LHC；欧洲核子研究中心，瑞士）碰撞中同时发生两个（或更多）硬子散射的事件的选择和分析。这种双（多）子散射的模拟涉及双（多）分布函数。回顾了可以从量子色动力学中提取的这些函数的性质。