In the realm of high-energy physics and quantum chromodynamics (QCD), a team of researchers from the University of Connecticut, E. Iancu, D. N. Triantafyllopoulos, S. Y. Wei, and F. Yuan, have delved into the intricacies of diffractive jet production in electron-nucleus collisions. Their work, published in the Journal of High Energy Physics, explores the quantum evolutions of the diffractive transverse-momentum dependent gluon distribution, shedding light on the complex dynamics of gluon interactions at high energies.
The researchers focus on the diffractive production of jet pairs with transverse momenta significantly larger than the nuclear saturation momentum, a phenomenon described by the Colour Glass Condensate (CGC) framework. At the leading order of the QCD coupling, the di-jet cross-section exhibits transverse-momentum dependent (TMD) factorisation. This involves a gluon diffractive TMD distribution (DTMD) that is governed by gluon saturation and describes the transverse-momentum imbalance between the produced jets.
The study delves into the next-to-leading corrections that generate various quantum evolutions of the diffractive gluon distribution. Specifically, the researchers concentrate on the Collins-Soper-Sterman (CSS) evolution, which illustrates how the gluon DTMD changes with the increase of the ‘hard scale’—the typical transverse momentum of the di-jets. They examine two representations of the CSS equation: one in transverse-momentum space and the other in transverse-coordinate space. Although these representations are related by a Fourier transform, they are not fully equivalent due to their respective boundary conditions.
These boundary conditions encapsulate the fundamental physics of gluon saturation, along with the effects of two other types of quantum evolution: the BK/JIMWLK evolution over the rapidity gap (‘inside the Pomeron’) and the DGLAP evolution outside the rapidity gap (‘within the diffractive system’). The researchers demonstrate that, thanks to gluon saturation, both the boundary conditions and the CSS solutions can be computed entirely from first principles, without relying on non-perturbative physics. Their numerical findings reveal a good agreement between the CSS solutions in the two representations.
For the energy sector, this research provides a deeper understanding of the fundamental interactions involving gluons, which are crucial for advancing technologies such as particle accelerators and high-energy physics experiments. The insights gained from this study could potentially contribute to the development of more efficient and precise energy technologies, although direct applications may still be in the realm of fundamental research.
This article is based on research available at arXiv.