Particle reactions at the highest energies have shaped our understanding of the fundamental constituents of matter and their interactions. Key to this is to reliably predict and interpret the complex final states and observables in high-energy collisions.
The observation of jets and other structure calls for the use of resummed perturbation theory, effective field theories, and Monte Carlo event generators, all of which are built on the infrared structure of scattering amplitudes in Quantum Chromodynamics (QCD). Factorization and evolution will in general mix color states, and only for certain observables, exploiting QCD coherence or the crude limit of large number of color charges $N_c$, simple universal functions and probabilistic algorithms emerge. A wealth of possibly rich phenomenology and contributions to the most accurate description of jets are thereby neglected.
This workshop will bring together the key players who have pushed factorization and evolution in color space beyond the large-$N_c$ limit to compare the different approaches. We will thereby build bridges between different communities, and compare theoretical frameworks, evaluate the phenomenological impact as well as the understanding of infrared structure.
The workshop is schduled to last two weeks, with most participants expected to attend for one or both weeks. The topics to be covered will be
- Emergence and Structure of Evolution Equations in Color Space
Relating parton shower algorithms, the JIMWLK equations, and the RG equations arising in EFTs, and investigating their origins. - Glauber Exchanges and Factorization Violation in QCD
Comparing the formalisms addressing Glauber physics, investigating a path to a generalized factorization framework for processes sensitive to Glauber effects. - Phenomenological Implications of Superleading Logarithms
Comparing existing frameworks to treat non-global logarithms, and incorporating these effects into theoretical predictions. - The Physics of Color Reconnection
Investigating non-perturbative effects beyond the large-$N_c$ limit, and interfacing to perturbative evolution by relating amplitude evolution and the effective field theory analysis - (Colour) Bases and Amplitude Evolution
Investigating generalisations of colour cases to include e.g. (iso)spin, and evaluating their suitability for analytic or numerical applications, as well as for insights into soft QCD physics.
The workshop will include overview talks held by experts in the field focusing on the key conceptual and technical challenges that must be addressed, also serving as reviews of the respective fields. In between these talks, dedicated discussion sessions will be held to foster an exchange of ideas between the different communities. In addition, a number of shorter presentations are planned to allow the junior participants to share their research results.
