Projected Energy Correlators: Two-Loop Jet Functions and NNLL Resummation
Pith reviewed 2026-06-28 13:25 UTC · model grok-4.3
The pith
Two-loop jet functions enable NNLL resummation of projected N-point energy correlators up to N=6.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The key new ingredient is the two-loop jet function for N=4,5,6 computed using Integration-by-Parts and differential equations, which permits the NNLL resummation of projected N-point energy correlators up to N=6 matched to fixed-order NLO predictions, including leading non-perturbative corrections described by two universal soft matrix elements.
What carries the argument
Two-loop jet function for N=4,5,6 computed semi-analytically via Integration-by-Parts and differential equations.
If this is right
- The matched NNLL distributions for ENCs up to N=6 can be compared with parton-shower simulations.
- Sensitivity of the spectra and their ratios to alpha_s and the soft matrix elements can be analyzed.
- Higher-point projected energy correlators achieve quantitative control at NNLL accuracy.
- This opens the possibility for future alpha_s extractions with complementary systematics.
Where Pith is reading between the lines
- The anomalous dimensions for (N-1)-point correlators governing the evolution of the soft matrix elements could be used to relate corrections across different N.
- Ratios of higher N correlators to the two-point one might reduce experimental and theoretical uncertainties in measurements.
- Applying similar methods to other processes or observables could broaden the use of energy correlators in QCD studies.
Load-bearing premise
The leading non-perturbative corrections are described by two universal soft matrix elements of order Lambda_QCD whose evolution is governed by anomalous dimensions for (N-1)-point correlators.
What would settle it
A direct computation of the jet function at three loops or a comparison with experimental data showing significant deviation from the NNLL prediction after accounting for the included power corrections would falsify the claimed accuracy.
read the original abstract
We present the next-to-next-to-leading logarithmic (NNLL) collinear resummation of projected $N$-point energy correlators (ENCs) up to $N=6$, matched to fixed-order predictions at NLO, in both electron-positron annihilation and Higgs decay to gluons. The key new ingredient is the two-loop jet function for $N=4,5,6$, which we compute semi-analytically using Integration-by-Parts and differential equations. We further include the leading non-perturbative corrections for ENCs, described by two universal soft matrix elements $\overline{\Omega}_{1q},\overline{\Omega}_{1g}$ of order $\Lambda_{\rm QCD}$, whose evolution is governed by anomalous dimensions for $(N-1)$-point correlators. The matched distributions are compared with parton-shower simulations from Pythia8 and Herwig7, and we study the sensitivity of both the absolute spectra and their ratios to the two-point energy correlator under variations of $\alpha_s$ and $\overline{\Omega}_{1q,1g}$. Our results show that higher-point projected energy correlators are now under quantitative control at NNLL accuracy, opening the door to future $\alpha_s$ extractions with complementary systematics.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper presents NNLL collinear resummation of projected N-point energy correlators (ENCs) up to N=6 in e+e- annihilation and Higgs decay to gluons, matched to NLO fixed order. The central technical advance is the semi-analytic computation of the two-loop jet functions for N=4,5,6 via integration-by-parts reduction and differential equations. Leading non-perturbative power corrections are modeled by two universal soft matrix elements Ω̅1q and Ω̅1g whose evolution follows (N-1)-point anomalous dimensions. Results are compared to Pythia8 and Herwig7 parton showers, with studies of sensitivity to αs and the soft parameters in both absolute spectra and ratios to the two-point correlator.
Significance. If the two-loop jet-function results hold, the work brings projected ENCs under quantitative NNLL control, providing a new set of observables for αs extractions whose systematics are complementary to event shapes. The explicit IBP+DE computation of the N=4,5,6 jet functions and the consistent matching plus power-correction framework constitute a clear technical contribution to the precision QCD literature.
minor comments (1)
- The abstract and introduction would benefit from a brief statement of the kinematic cuts or fiducial phase-space definitions used for the N-point correlators when comparing to parton showers.
Simulated Author's Rebuttal
We thank the referee for their positive assessment of the manuscript, recognition of the technical advances in the two-loop jet functions, and recommendation to accept. There are no major comments to address.
Circularity Check
No significant circularity detected
full rationale
The paper computes two-loop jet functions for N=4,5,6 directly via Integration-by-Parts reduction and differential equations, then performs standard NNLL collinear resummation matched to NLO fixed order. Non-perturbative power corrections are introduced explicitly as an assumption using two universal soft matrix elements whose evolution follows from known anomalous dimensions; these are not derived from or fitted to the perturbative results within the paper. No quoted equation or step reduces the claimed predictions to inputs by construction, and no load-bearing self-citation chain is exhibited. The derivation chain is therefore self-contained and employs standard field methods without internal reduction.
Axiom & Free-Parameter Ledger
free parameters (2)
- Ω̅1q
- Ω̅1g
axioms (2)
- domain assumption Collinear factorization and all-order resummation in perturbative QCD
- domain assumption Existence and universality of the two soft matrix elements governing power corrections
Reference graph
Works this paper leans on
-
[1]
G. F. Sterman,Jet Structure in e+ e- Annihilation with Massless Hadrons,ILL-TH-75-32 (1975)
1975
-
[2]
N. A. Sveshnikov and F. V. Tkachov,Jets and quantum field theory,Phys. Lett. B382 (1996) 403–408, [hep-ph/9512370]
Pith/arXiv arXiv 1996
-
[3]
F. V. Tkachov,Measuring multi - jet structure of hadronic energy flow or What is a jet?, Int. J. Mod. Phys. A12(1997) 5411–5529, [hep-ph/9601308]
Pith/arXiv arXiv 1997
-
[4]
G. P. Korchemsky and G. F. Sterman,Power corrections to event shapes and factorization, Nucl. Phys. B555(1999) 335–351, [hep-ph/9902341]
Pith/arXiv arXiv 1999
-
[5]
D. M. Hofman and J. Maldacena,Conformal collider physics: Energy and charge correlations,JHEP05(2008) 012, [arXiv:0803.1467]
Pith/arXiv arXiv 2008
-
[6]
M. Kologlu, P. Kravchuk, D. Simmons-Duffin, and A. Zhiboedov,The light-ray OPE and conformal colliders,JHEP01(2021) 128, [arXiv:1905.01311]. – 56 –
arXiv 2021
-
[7]
I. Moult and H. X. Zhu,Energy Correlators: A Journey From Theory to Experiment, arXiv:2506.09119
-
[8]
C. L. Basham, L. S. Brown, S. D. Ellis, and S. T. Love,Energy Correlations in electron - Positron Annihilation: Testing QCD,Phys. Rev. Lett.41(1978) 1585
1978
-
[9]
C. L. Basham, L. S. Brown, S. D. Ellis, and S. T. Love,Energy Correlations in electron-Positron Annihilation in Quantum Chromodynamics: Asymptotically Free Perturbation Theory,Phys. Rev. D19(1979) 2018
1979
-
[10]
C. L. Basham, L. S. Brown, S. D. Ellis, and S. T. Love,Energy Correlations in Perturbative Quantum Chromodynamics: A Conjecture for All Orders,Phys. Lett. B85(1979) 297–299
1979
-
[11]
C. L. Basham, L. S. Brown, S. D. Ellis, and S. T. Love,Electron - Positron Annihilation Energy Pattern in Quantum Chromodynamics: Asymptotically Free Perturbation Theory, Phys. Rev. D17(1978) 2298
1978
-
[12]
A. V. Belitsky, S. Hohenegger, G. P. Korchemsky, E. Sokatchev, and A. Zhiboedov, Energy-Energy Correlations in N=4 Supersymmetric Yang-Mills Theory,Phys. Rev. Lett. 112(2014), no. 7 071601, [arXiv:1311.6800]
Pith/arXiv arXiv 2014
-
[13]
J. M. Henn, E. Sokatchev, K. Yan, and A. Zhiboedov,Energy-energy correlation inN=4 super Yang-Mills theory at next-to-next-to-leading order,Phys. Rev. D100(2019), no. 3 036010, [arXiv:1903.05314]
arXiv 2019
-
[14]
L. J. Dixon, M.-X. Luo, V. Shtabovenko, T.-Z. Yang, and H. X. Zhu,Analytical Computation of Energy-Energy Correlation at Next-to-Leading Order in QCD,Phys. Rev. Lett.120(2018), no. 10 102001, [arXiv:1801.03219]
Pith/arXiv arXiv 2018
-
[15]
M.-X. Luo, V. Shtabovenko, T.-Z. Yang, and H. X. Zhu,Analytic Next-To-Leading Order Calculation of Energy-Energy Correlation in Gluon-Initiated Higgs Decays,JHEP06(2019) 037, [arXiv:1903.07277]
Pith/arXiv arXiv 2019
-
[16]
J. Gao, V. Shtabovenko, and T.-Z. Yang,Energy-energy correlation in hadronic Higgs decays: analytic results and phenomenology at NLO,JHEP02(2021) 210, [arXiv:2012.14188]. [17]ALEPHCollaboration, D. Decamp et al.,Measurement of alpha-s from the structure of particle clusters produced in hadronic Z decays,Phys. Lett. B257(1991) 479–491. [18]DELPHICollaborat...
arXiv 2021
- [17]
-
[18]
H. Bossi, Y.-C. Chen, Y. Chen, J. Zhang, G. M. Innocenti, A. Badea, A. Baty, M. Maggi, C. McGinn, and Y.-J. Lee,Analysis note: measurement of energy-energy correlator ine+e− collisions at91GeV with archived ALEPH data,arXiv:2505.11828. [21]Electron-Positron AllianceCollaboration, H. Bossi et al.,Energy Correlators from Partons to Hadrons: Unveiling the Dy...
-
[19]
J. Zhang, T.-A. Sheng, Y.-C. Chen, H. Bossi, A. Badea, A. Baty, C. McGinn, Y.-J. Lee, and Y. Chen,Analysis note: measurement of thrust and track energy-energy correlator in e+e- collisions at 91.2 GeV with DELPHI open data,arXiv:2510.18762. – 57 –
-
[20]
L. J. Dixon, I. Moult, and H. X. Zhu,Collinear limit of the energy-energy correlator,Phys. Rev. D100(2019), no. 1 014009, [arXiv:1905.01310]
Pith/arXiv arXiv 2019
-
[21]
G. P. Korchemsky,Energy correlations in the end-point region,JHEP01(2020) 008, [arXiv:1905.01444]
arXiv 2020
- [22]
-
[23]
H. Chen, M.-X. Luo, I. Moult, T.-Z. Yang, X. Zhang, and H. X. Zhu,Three point energy correlators in the collinear limit: symmetries, dualities and analytic results,JHEP08 (2020) 028, [arXiv:1912.11050]
arXiv 2020
-
[24]
T.-Z. Yang and X. Zhang,Analytic Computation of three-point energy correlator in QCD, JHEP09(2022) 006, [arXiv:2208.01051]
arXiv 2022
-
[25]
T.-Z. Yang and X. Zhang,Three-point energy correlators in hadronic Higgs boson decays, Phys. Rev. D109(2024), no. 11 114036, [arXiv:2402.05174]
arXiv 2024
-
[26]
D. Chicherin, I. Moult, E. Sokatchev, K. Yan, and Y. Zhu,Collinear limit of the four-point energy correlator in N=4 supersymmetric Yang-Mills theory,Phys. Rev. D110(2024), no. 9 L091901, [arXiv:2401.06463]
arXiv 2024
-
[27]
S. He, X. Jiang, Q. Yang, and Y.-Q. Zhang,From squared amplitudes to energy correlators, arXiv:2408.04222
-
[28]
H. Chen, I. Moult, X. Zhang, and H. X. Zhu,Rethinking jets with energy correlators: Tracks, resummation, and analytic continuation,Phys. Rev. D102(2020), no. 5 054012, [arXiv:2004.11381]
arXiv 2020
-
[29]
P. T. Komiske, I. Moult, J. Thaler, and H. X. Zhu,Analyzing N-Point Energy Correlators inside Jets with CMS Open Data,Phys. Rev. Lett.130(2023), no. 5 051901, [arXiv:2201.07800]
arXiv 2023
- [30]
- [31]
-
[32]
Z.-B. Kang, A. Metz, D. Pitonyak, and C. Zhang,Dihadron Fragmentation Framework for Near-Side Energy-Energy Correlators,Phys. Rev. Lett.136(2026), no. 8 081905, [arXiv:2507.17444]
arXiv 2026
-
[33]
K. Lee, B. Meçaj, and I. Moult,Conformal collider physics meets LHC data,Phys. Rev. D 111(2025), no. 1 L011502, [arXiv:2205.03414]
arXiv 2025
-
[34]
W. Chen, J. Gao, Y. Li, Z. Xu, X. Zhang, and H. X. Zhu,NNLL resummation for projected three-point energy correlator,JHEP05(2024) 043, [arXiv:2307.07510]. [38]Flavour Lattice A veraging Group (FLAG)Collaboration, Y. Aoki et al.,FLAG review 2024,Phys. Rev. D113(2026), no. 1 014508, [arXiv:2411.04268]
arXiv 2024
-
[35]
R. Abbate, M. Fickinger, A. H. Hoang, V. Mateu, and I. W. Stewart,Thrust atN3LLwith Power Corrections and a Precision Global Fit forαs(mZ),Phys. Rev. D83(2011) 074021, [arXiv:1006.3080]. – 58 –
Pith/arXiv arXiv 2011
-
[36]
T. Becher and M. D. Schwartz,A precise determination ofαs from LEP thrust data using effective field theory,JHEP07(2008) 034, [arXiv:0803.0342]
Pith/arXiv arXiv 2008
-
[37]
A. H. Hoang, D. W. Kolodrubetz, V. Mateu, and I. W. Stewart,Precise determination of αs from theC-parameter distribution,Phys. Rev. D91(2015), no. 9 094018, [arXiv:1501.04111]
Pith/arXiv arXiv 2015
-
[38]
A. H. Hoang, D. W. Kolodrubetz, V. Mateu, and I. W. Stewart,C-parameter distribution at N3LL’ including power corrections,Phys. Rev. D91(2015), no. 9 094017, [arXiv:1411.6633]
Pith/arXiv arXiv 2015
-
[39]
M. A. Benitez, A. H. Hoang, V. Mateu, I. W. Stewart, and G. Vita,On determining αs(mZ) from dijets in e+e− thrust,JHEP07(2025) 249, [arXiv:2412.15164]
arXiv 2025
-
[40]
M. A. Benitez, A. Bhattacharya, A. H. Hoang, V. Mateu, M. D. Schwartz, I. W. Stewart, and X. Zhang,A Precise Determination ofαs from the Heavy Jet Mass Distribution, arXiv:2502.12253
- [41]
-
[42]
d’Enterria et al.,The strong coupling constant: state of the art and the decade ahead,J
D. d’Enterria et al.,The strong coupling constant: state of the art and the decade ahead,J. Phys. G51(2024), no. 9 090501, [arXiv:2203.08271]. [47]CMSCollaboration, A. Hayrapetyan et al.,Measurement of Energy Correlators inside Jets and Determination of the Strong CouplingαS(mZ),Phys. Rev. Lett.133(2024), no. 7 071903, [arXiv:2402.13864]. [48]FCCCollabora...
arXiv 2024
-
[43]
H. Chen, P. F. Monni, Z. Xu, and H. X. Zhu,Perturbative evolution of hadronization effects in energy correlators,talk by Hao Chen at SCET 2024(2024)
2024
-
[44]
K. Lee, A. Pathak, I. W. Stewart, and Z. Sun,Nonperturbative Effects in Energy Correlators: From Characterizing Confinement Transition to Improvingαs Extraction, Phys. Rev. Lett.133(2024), no. 23 231902, [arXiv:2405.19396]
arXiv 2024
-
[45]
H. Chen, P. F. Monni, Z. Xu, and H. X. Zhu,Scaling Violation in Power Corrections to Energy Correlators from the Light-Ray Operator Product Expansion,Phys. Rev. Lett.133 (2024), no. 23 231901, [arXiv:2406.06668]
arXiv 2024
-
[46]
C. Lee and G. F. Sterman,Universality of nonperturbative effects in event shapes,eConf C0601121(2006) A001, [hep-ph/0603066]
Pith/arXiv arXiv 2006
-
[47]
A. Budhraja, H. Chen, and W. J. Waalewijn,ν-point energy correletors with FastEEC: Small-x physics from LHC jets,Phys. Lett. B861(2025) 139239, [arXiv:2409.12235]
arXiv 2025
-
[48]
G. Somogyi, Z. Trocsanyi, and V. Del Duca,A Subtraction scheme for computing QCD jet cross sections at NNLO: Regularization of doubly-real emissions,JHEP01(2007) 070, [hep-ph/0609042]
Pith/arXiv arXiv 2007
-
[49]
G. Somogyi and Z. Trocsanyi,A Subtraction scheme for computing QCD jet cross sections at NNLO: Regularization of real-virtual emission,JHEP01(2007) 052, [hep-ph/0609043]. – 59 –
Pith/arXiv arXiv 2007
-
[50]
U. Aglietti, V. Del Duca, C. Duhr, G. Somogyi, and Z. Trocsanyi,Analytic integration of real-virtual counterterms in NNLO jet cross sections. I.,JHEP09(2008) 107, [arXiv:0807.0514]
Pith/arXiv arXiv 2008
-
[51]
S. Catani and M. H. Seymour,The Dipole formalism for the calculation of QCD jet cross-sections at next-to-leading order,Phys. Lett. B378(1996) 287–301, [hep-ph/9602277]
Pith/arXiv arXiv 1996
-
[52]
S. Catani and M. H. Seymour,A General algorithm for calculating jet cross-sections in NLO QCD,Nucl. Phys. B485(1997) 291–419, [hep-ph/9605323]. [Erratum: Nucl.Phys.B 510, 503–504 (1998)]
Pith/arXiv arXiv 1997
-
[53]
A. Gehrmann-De Ridder, T. Gehrmann, E. W. N. Glover, and G. Heinrich,EERAD3: Event shapes and jet rates in electron-positron annihilation at orderα3 s,Comput. Phys. Commun.185(2014) 3331, [arXiv:1402.4140]
Pith/arXiv arXiv 2014
-
[54]
B. C. Aveleira, A. Gehrmann-De Ridder, T. Gehrmann, N. Glover, G. Heinrich, and C. T. Preuss,EERAD3 version 2: QCD corrections in hadronic colour-singlet decays,SciPost Phys. Codeb.59(2025) 1, [arXiv:2503.20610]
arXiv 2025
-
[55]
P. J. Rijken and W. L. van Neerven,O (alpha-s**2) contributions to the longitudinal fragmentation function in e+ e- annihilation,Phys. Lett. B386(1996) 422–428, [hep-ph/9604436]
Pith/arXiv arXiv 1996
-
[56]
P. J. Rijken and W. L. van Neerven,Higher order QCD corrections to the transverse and longitudinal fragmentation functions in electron - positron annihilation,Nucl. Phys. B487 (1997) 233–282, [hep-ph/9609377]
Pith/arXiv arXiv 1997
-
[57]
P. J. Rijken and W. L. van Neerven,O (alpha-s**2) contributions to the asymmetric fragmentation function in e+ e- annihilation,Phys. Lett. B392(1997) 207–215, [hep-ph/9609379]
Pith/arXiv arXiv 1997
-
[58]
A. Mitov and S.-O. Moch,QCD Corrections to Semi-Inclusive Hadron Production in Electron-Positron Annihilation at Two Loops,Nucl. Phys. B751(2006) 18–52, [hep-ph/0604160]
Pith/arXiv arXiv 2006
-
[59]
A. Mitov, S. Moch, and A. Vogt,Next-to-Next-to-Leading Order Evolution of Non-Singlet Fragmentation Functions,Phys. Lett. B638(2006) 61–67, [hep-ph/0604053]
Pith/arXiv arXiv 2006
-
[60]
S. Moch and A. Vogt,On third-order timelike splitting functions and top-mediated Higgs decay into hadrons,Phys. Lett. B659(2008) 290–296, [arXiv:0709.3899]
Pith/arXiv arXiv 2008
-
[61]
A. A. Almasy, S. Moch, and A. Vogt,On the Next-to-Next-to-Leading Order Evolution of Flavour-Singlet Fragmentation Functions,Nucl. Phys. B854(2012) 133–152, [arXiv:1107.2263]
Pith/arXiv arXiv 2012
-
[62]
H. Chen, T.-Z. Yang, H. X. Zhu, and Y. J. Zhu,Analytic Continuation and Reciprocity Relation for Collinear Splitting in QCD,Chin. Phys. C45(2021), no. 4 043101, [arXiv:2006.10534]
arXiv 2021
-
[63]
T. Gehrmann, A. von Manteuffel, V. Sotnikov, and T.-Z. Yang,CompleteN2 f contributions to four-loop pure-singlet splitting functions,JHEP01(2024) 029, [arXiv:2308.07958]
arXiv 2024
-
[64]
G. Falcioni, F. Herzog, S. Moch, and A. Vogt,Four-loop splitting functions in QCD – The quark-quark case,Phys. Lett. B842(2023) 137944, [arXiv:2302.07593]
arXiv 2023
-
[65]
G. Falcioni, F. Herzog, S. Moch, and A. Vogt,Four-loop splitting functions in QCD – The gluon-to-quark case,Phys. Lett. B846(2023) 138215, [arXiv:2307.04158]. – 60 –
arXiv 2023
-
[66]
G. Falcioni, F. Herzog, S. Moch, A. Pelloni, and A. Vogt,Four-loop splitting functions in QCD – The quark-to-gluon case,Phys. Lett. B856(2024) 138906, [arXiv:2404.09701]
arXiv 2024
-
[67]
G. Falcioni, F. Herzog, S. Moch, A. Pelloni, and A. Vogt,Four-loop splitting functions in QCD – the gluon-gluon case –,Phys. Lett. B860(2025) 139194, [arXiv:2410.08089]
arXiv 2025
-
[68]
G. Falcioni, F. Herzog, S. Moch, A. Pelloni, and A. Vogt,Additional results on the four-loop flavour-singlet splitting functions in QCD,Phys. Lett. B875(2026) 140278, [arXiv:2512.10783]
arXiv 2026
-
[69]
Nogueira,Automatic feynman graph generation,Journal of Computational Physics105 (1993), no
P. Nogueira,Automatic feynman graph generation,Journal of Computational Physics105 (1993), no. 2 279–289
1993
-
[70]
J. A. M. Vermaseren,New features of FORM,math-ph/0010025
-
[71]
J. Kuipers, T. Ueda, J. A. M. Vermaseren, and J. Vollinga,FORM version 4.0,Comput. Phys. Commun.184(2013) 1453–1467, [arXiv:1203.6543]
Pith/arXiv arXiv 2013
- [72]
-
[73]
T. van Ritbergen, A. N. Schellekens, and J. A. M. Vermaseren,Group theory factors for Feynman diagrams,Int. J. Mod. Phys. A14(1999) 41–96, [hep-ph/9802376]
Pith/arXiv arXiv 1999
-
[74]
Mertig, M
R. Mertig, M. Bohm, and A. Denner,FEYN CALC: Computer algebraic calculation of Feynman amplitudes,Comput. Phys. Commun.64(1991) 345–359
1991
-
[75]
V. Shtabovenko, R. Mertig, and F. Orellana,New Developments in FeynCalc 9.0,Comput. Phys. Commun.207(2016) 432–444, [arXiv:1601.01167]
Pith/arXiv arXiv 2016
-
[76]
V. Shtabovenko, R. Mertig, and F. Orellana,FeynCalc 9.3: New features and improvements,Comput. Phys. Commun.256(2020) 107478, [arXiv:2001.04407]
Pith/arXiv arXiv 2020
-
[77]
V. Shtabovenko, R. Mertig, and F. Orellana,FeynCalc 10: Do multiloop integrals dream of computer codes?,arXiv:2312.14089
-
[78]
R. N. Lee,Presenting LiteRed: a tool for the Loop InTEgrals REDuction, arXiv:1212.2685
-
[79]
R. N. Lee,LiteRed 1.4: a powerful tool for reduction of multiloop integrals,J. Phys. Conf. Ser.523(2014) 012059, [arXiv:1310.1145]
Pith/arXiv arXiv 2014
-
[80]
A. V. Smirnov and F. S. Chukharev,FIRE6: Feynman Integral REduction with modular arithmetic,Comput. Phys. Commun.247(2020) 106877, [arXiv:1901.07808]
arXiv 2020
discussion (0)
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