Three NCBJ scientists received grants in the 10th edition of the NCN SONATA BIS competition. One of them is Dr. Guillaume Clement Beuf from the Department of Theoretical Physics. The project 'The search of precision in nonlinear high-energy Quantum Chromodynamics' focuses on the theory's regime, which can be studied by high-energy particle collisions without wide-angle scattering or heavy particle production. The author describes the motivation and research he intends to conduct:

In particle physics, the strong nuclear force is responsible for the binding of quarks and gluons into protons and neutrons and then into nuclei. Quantum Chromodynamics (QCD) is well established as the correct theory for the strong nuclear force, and for the dynamics of quark and gluons in general.

For particle collisions involving a large angle scattering or the production of heavy particles, which are driven by short-range QCD interactions, it is possible to derive very precise theoretical predictions from QCD, which are in agreement with experimental data. By contrast, QCD dynamics becomes extremely challenging in the low energy regime, due to the increase of the effective QCD coupling at larger distances, so that for example the formation of proton and neutrons is understood only at the qualitative level.

Theoretically, a third regime of QCD should exist, which can be probed by high-energy particle collisions without large angle scattering nor heavy particle production. In such case, the collision effectively takes a brief snapshot of the incoming proton(s), revealing a large number of gluons of very short lifetimes. This leads to a fully nonlinear regime of QCD, called gluon saturation, driven by multiple gluon interactions due to the large density of gluons.

Due to the lack of precision of existing theoretical QCD predictions in the gluon saturation regime, it is not possible to find gluon saturation effects in the experimental data in an fully unambiguous way. The main aim of my project is to improve the theory of gluon saturation by including corrections of various types, in order to obtain precise predictions for high-energy processes at the Large Hadron Collider at CERN and at the future Electron Ion Collider in the USA.