AntScat · Interactions among Coherent Objects and the Origin of Collectivity in QCD at Colliders

The surprising findings of collective effects in nucleon-nucleus and nucleon-nucleon collisions (and very recently even in electron-positron collisions), previously thought to be exclusive to large systems such as nucleus-nucleus collisions, pose an important challenge to the particle physics community. Both from the heavy-ion and the high-energy communities, intense efforts are devoted to gain a better understanding of the origin of collectivity in QCD. This project revolves around the theoretical study of the interactions among coherent objects and their phenomenological implications. So far, these type of interactions have been absent in the respective state-of-the-art descriptions of the dynamical evolution of QCD at colliders adopted by both communities. The first goal of this project will be to compute the cross-sections for a new set of processes, ranging from the interaction of on-shell particles with colored dipoles to the interactions among dipoles with other dipoles. As a result of these interactions, broadening and stimulated radiation can take place. The features of the dipoles, such as their mass, are imprinted in the scattered object due to the phenomenon of color and quantum interference. These physics translate in the appearance of non-trivial correlations among these objects. A second aspect of the project will consist in the phenomenological modeling that these correlations can have in a) QCD parton showers, the natural scenario from the high-energy front, where interactions among parton and multi-parton objects will be added to the typical splitting processes and b) QCD effective kinetic theory, the natural scenario from the heavy-ion front, where the inclusion of the coherent objects can be modeled by considering them as unstable particles. A detailed study of the observable effects that these new correlations can induce will shed light on the role played by the physics of quantum interference in describing the origin of collectivity in QCD.