SciPost Submission Page
Structure of non-global logarithms with Cambridge/Aachen clustering
by K. Khelifa-Kerfa
Submission summary
| Authors (as registered SciPost users): | Kamel Khelifa-Kerfa |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2511.14947v2 (pdf) |
| Date submitted: | Feb. 10, 2026, 4:25 p.m. |
| Submitted by: | Kamel Khelifa-Kerfa |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Computational, Phenomenological |
The author(s) disclose that the following generative AI tools have been used in the preparation of this submission:
Help in writing the python code
Proofreading the manuscript
Abstract
We determine the structure of both Abelian and non-Abelian non-global logarithms up to four loops for $e^+e^-$ processes in perturbative QCD, where final-state jets are defined using the Cambridge--Aachen (C/A) clustering algorithm. The calculations are performed within the soft (eikonal) approximation using strong-energy ordering of the final-state partons for the case of the dijet invariant mass. The resulting expressions include full colour and complete jet-radius dependence. Compared to the anti-$k_t$ and $k_t$ clustering algorithms, the C/A distribution minimises the impact of these non-global logarithms, making it the preferred choice among the three algorithms.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Author comments upon resubmission
Reply to Report 1:
Regarding Gnole, we plan to investigate implementing both the kt and C/A algorithms. If successful (even if only in the large-Nc limit), this will constitute an important addition to the non-global community: it would enable automated resummation of non-global logarithms up to NL–NGLs for various jet algorithms, a capability not currently available in the literature.
Reply to Report 3 :
The way sequential recombination algorithms, particularly the kt and C/A algorithms, work has little to do with the fine details of a given non-global observable. The most important feature is that the non-global observable is defined over an exclusive region of phase space, where there are at least two regions, which we label "in" and "out". The net effect of these algorithms is to determine whether a given emission ends up in the "in" or "out" region, based on factors entering the definition of those algorithms. The methodology/strategy presented in this paper can be seen to apply to other observables, for example interjet energy flow (gaps between jets) and azimuthal decorrelation between leading jets.
List of changes
1/ A sentence stating that the calculations are performed for the dijet invariant mass has been added to the abstract (for clarification and precision).
2/ A sentence has been added to the third paragraph of the Introduction acknowledging developments at the amplitude level that incorporate subleading-colour effects.
3/ A sentence just above the Conclusion section has been added to note this observation.
4/ (A) The bottom-left panel of Fig. 8 has been modified to align with the other panels. (B) The colour scheme of Fig. 9 has been updated.
5/ Equation (11) has been corrected.
6/ A sentence clarifying the four terms appearing in Equation (23) has been added immediately below that equation.