Recognition: unknown
Form factors of mathscr{N}=4 self-dual Yang-Mills from the chiral algebra bootstrap
Pith reviewed 2026-05-09 23:23 UTC · model grok-4.3
The pith
The chiral algebra bootstrap yields all-loop holomorphic collinear splitting functions and new two-loop form factors for self-dual N=4 super Yang-Mills.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We use a combination of twistor space input, Koszul duality, supersymmetry, and associativity to obtain the all-loop holomorphic collinear splitting functions for SDSYM. We also use associativity to provide a simple proof of the conjecture that there are no double-poles in the loop-level OPEs for this theory. We conclude by computing several form factors, including both a reproduction of several known results and novel form factors up to two loops involving insertions of powers of the anti-self-dual field strength. These form factors compute a supersymmetric version of Higgs amplitudes in the self-dual sector.
What carries the argument
The chiral algebra bootstrap, in which holomorphic collinear splitting functions (equivalently celestial chiral algebra OPEs) recursively generate loop-level form factors from initial data supplied by twistor space and Koszul duality.
If this is right
- All-loop holomorphic collinear splitting functions for SDSYM are now determined explicitly.
- Loop-level OPEs in the theory contain no double poles.
- Form factors up to two loops, including new ones with anti-self-dual field strength insertions, are available in closed form.
- These form factors equal supersymmetric Higgs amplitudes in the self-dual sector.
- The method works for other quantum-integrable self-dual gauge theories once the same initial data are supplied.
Where Pith is reading between the lines
- The same bootstrap could be run at higher loops to produce three-loop and beyond form factors without new input data.
- Explicit OPEs obtained here supply concrete data for testing conjectures in celestial holography.
- Comparison of these self-dual form factors with full-theory Higgs amplitudes would quantify the contribution of the anti-self-dual sector.
- Absence of double poles may be linked to the infinite-dimensional symmetry algebra that renders the theory integrable.
Load-bearing premise
The chiral algebra bootstrap program applies directly to self-dual N=4 Yang-Mills, with all singularities of the form factors generated exactly by the holomorphic collinear splitting functions.
What would settle it
An independent twistor-space or unitarity-based computation of any two-loop form factor containing an insertion of the anti-self-dual field strength that differs from the expression obtained here would falsify the bootstrap result.
read the original abstract
The chiral algebra bootstrap (CAB) is a novel bootstrap program for form factors in quantum-integrable self-dual gauge theories, some of which in turn are helicity amplitudes in the corresponding gauge theories. The singularities that recursively generate a given (loop-level) form factor are holomorphic collinear splitting functions, equivalently celestial chiral algebra OPEs, of the self-dual theory. In this note, we apply the chiral algebra bootstrap to the simple example of self-dual 4d $\mathscr{N}=4$ super Yang-Mills (SDSYM). We use a combination of twistor space input, Koszul duality, supersymmetry, and associativity to obtain the all-loop holomorphic collinear splitting functions for SDSYM. We also use associativity to provide a simple proof of the conjecture that there are no double-poles in the loop-level OPEs for this theory. We conclude by computing several form factors, including both a reproduction of several known results and novel form factors up to two loops involving insertions of powers of the anti-self-dual field strength. These form factors compute a supersymmetric version of Higgs amplitudes in the self-dual sector. Detailed sample computations are provided to familiarize the reader with the CAB method.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper applies the chiral algebra bootstrap (CAB) to self-dual N=4 super Yang-Mills (SDSYM). It combines twistor space input, Koszul duality, supersymmetry, and associativity to derive the all-loop holomorphic collinear splitting functions (equated to celestial chiral algebra OPEs). Associativity is used to prove the absence of double poles in the loop-level OPEs. The work concludes with explicit computations of several form factors up to two loops, reproducing known results and providing novel ones involving insertions of powers of the anti-self-dual field strength, interpreted as supersymmetric Higgs amplitudes in the self-dual sector. Detailed sample computations are included to illustrate the method.
Significance. If the central derivations hold, this advances the CAB program by furnishing all-loop splitting functions for SDSYM and a consistency proof for OPE singularities, while delivering concrete form factor results that connect twistor methods to celestial algebras. The reproduction of known results alongside new two-loop computations, plus the sample calculations, strengthens the case for the bootstrap's applicability to self-dual integrable theories.
major comments (2)
- [Main derivation and abstract] The derivation of the all-loop holomorphic collinear splitting functions rests on the claim that twistor space input combined with Koszul duality supplies complete initial data that, together with supersymmetry and associativity, uniquely determines the functions at all orders. This assumption is load-bearing for both the all-loop claim and the novel two-loop form factors; the manuscript should explicitly address whether loop-dependent corrections or additional constraints could arise beyond the provided data (see the discussion following the abstract and the main derivation section).
- [Proof of no double poles] The associativity-based proof that there are no double poles in the loop-level OPEs is presented as straightforward, but the specific associativity relations invoked and their application across loop orders require more detail to confirm they close without external input or hidden assumptions.
minor comments (3)
- The notation for splitting functions and OPEs would benefit from a dedicated table or explicit low-order examples early in the text to improve readability for readers new to CAB.
- [Introduction] References to prior CAB literature and twistor-space results should be expanded in the introduction to clarify the precise novelty of the SDSYM application.
- [Sample computations] The sample computations section is helpful but could include more intermediate steps for one of the novel two-loop form factors to aid verification.
Simulated Author's Rebuttal
We thank the referee for their careful reading of the manuscript and for highlighting the load-bearing aspects of the derivation. We agree that additional explicit discussion will strengthen the presentation and will revise the manuscript accordingly. Below we address each major comment in turn.
read point-by-point responses
-
Referee: [Main derivation and abstract] The derivation of the all-loop holomorphic collinear splitting functions rests on the claim that twistor space input combined with Koszul duality supplies complete initial data that, together with supersymmetry and associativity, uniquely determines the functions at all orders. This assumption is load-bearing for both the all-loop claim and the novel two-loop form factors; the manuscript should explicitly address whether loop-dependent corrections or additional constraints could arise beyond the provided data (see the discussion following the abstract and the main derivation section).
Authors: The twistor-space input together with Koszul duality furnishes the complete tree-level and one-loop data for the holomorphic collinear splitting functions. Supersymmetry then restricts the possible higher-loop structures, while associativity of the resulting celestial chiral algebra is used to fix all coefficients uniquely, as verified by the explicit two-loop form-factor computations that reproduce known results without introducing new parameters. We will add a short clarifying paragraph immediately after the abstract and in the main derivation section (around the discussion of the bootstrap closure) that explicitly states why no loop-dependent corrections or external constraints arise beyond the supplied initial data, supported by the consistency of the all-loop expressions with the associativity conditions. revision: yes
-
Referee: [Proof of no double poles] The associativity-based proof that there are no double poles in the loop-level OPEs is presented as straightforward, but the specific associativity relations invoked and their application across loop orders require more detail to confirm they close without external input or hidden assumptions.
Authors: The proof proceeds from the associativity of the OPEs in the celestial chiral algebra, specifically the requirement that the triple collinear limits satisfy the Jacobi identity at each loop order. We will expand the relevant subsection to display the explicit associativity relations (including the relevant three-point and four-point OPE associators) and walk through their application order by order, showing that they close on the all-loop splitting functions already derived and do not require additional external input. This elaboration will make transparent that the absence of double poles follows directly from the bootstrap data without hidden assumptions. revision: yes
Circularity Check
No significant circularity; derivation extends from external inputs to new results.
full rationale
The paper obtains all-loop holomorphic collinear splitting functions from twistor space input, Koszul duality, supersymmetry, and associativity, then applies these to compute form factors (reproducing known results and generating novel ones up to two loops). Associativity additionally supplies a consistency proof for the absence of double poles in OPEs. No quoted step equates a derived quantity to its own inputs by construction, renames a fit as a prediction, or reduces the central claim to a self-citation chain; the computations build outward from the stated initial data in a self-contained manner.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption The singularities that recursively generate a given (loop-level) form factor are holomorphic collinear splitting functions, equivalently celestial chiral algebra OPEs, of the self-dual theory.
- domain assumption Twistor space input and Koszul duality supply the initial data needed to bootstrap the splitting functions when combined with supersymmetry and associativity.
Reference graph
Works this paper leans on
- [1]
- [2]
- [3]
- [4]
- [5]
- [6]
-
[7]
A. Sever, A.G. Tumanov and M. Wilhelm,Operator Product Expansion for Form Factors,Phys. Rev. Lett.126(2021) 031602 [2009.11297]
-
[8]
A. Sever, A.G. Tumanov and M. Wilhelm,An Operator Product Expansion for Form Factors II. Born level,JHEP10(2021) 071 [2105.13367]
-
[9]
A. Sever, A.G. Tumanov and M. Wilhelm,An Operator Product Expansion for Form Factors III. Finite Coupling and Multi-Particle Contributions,JHEP03(2022) 128 [2112.10569]
-
[10]
B. Basso and A.G. Tumanov,Wilson loop duality and OPE for super form factors of half-BPS operators,JHEP02(2024) 022 [2308.08432]
-
[11]
L.J. Dixon, J.M. Drummond and J.M. Henn,Analytic result for the two-loop six-point NMHV amplitude in N=4 super Yang-Mills theory,JHEP01(2012) 024 [1111.1704]
-
[12]
L.J. Dixon, J.M. Drummond and J.M. Henn,Bootstrapping the three-loop hexagon,JHEP11 (2011) 023 [1108.4461]
-
[13]
L.J. Dixon, J.M. Drummond, M. von Hippel and J. Pennington,Hexagon functions and the three-loop remainder function,JHEP12(2013) 049 [1308.2276]. – 43 –
-
[14]
L.J. Dixon and M. von Hippel,Bootstrapping an NMHV amplitude through three loops,JHEP 10(2014) 065 [1408.1505]
-
[15]
L.J. Dixon, J.M. Drummond, C. Duhr and J. Pennington,The four-loop remainder function and multi-Regge behavior at NNLLA in planar N = 4 super-Yang-Mills theory,JHEP06(2014) 116 [1402.3300]
- [16]
- [17]
- [18]
-
[19]
L.J. Dixon, A.J. McLeod and M. Wilhelm,A Three-Point Form Factor Through Five Loops, JHEP04(2021) 147 [2012.12286]
- [20]
-
[21]
L.J. Dixon and Y.-T. Liu,An eight loop amplitude via antipodal duality,JHEP09(2023) 098 [2308.08199]
-
[22]
L.J. Dixon and S. Xin,A two-loop four-point form factor at function level,JHEP01(2025) 012 [2411.01571]
-
[23]
J.M. Drummond, G. Papathanasiou and M. Spradlin,A Symbol of Uniqueness: The Cluster Bootstrap for the 3-Loop MHV Heptagon,JHEP03(2015) 072 [1412.3763]
-
[24]
J. Drummond, J. Foster, ¨O. G¨ urdo˘ gan and G. Papathanasiou,Cluster adjacency and the four-loop NMHV heptagon,JHEP03(2019) 087 [1812.04640]
-
[25]
S. Caron-Huot, L.J. Dixon, A. McLeod and M. von Hippel,Bootstrapping a Five-Loop Amplitude Using Steinmann Relations,Phys. Rev. Lett.117(2016) 241601 [1609.00669]
-
[26]
S. Caron-Huot, L.J. Dixon, F. Dulat, M. von Hippel, A.J. McLeod and G. Papathanasiou, Six-Gluon amplitudes in planarN= 4 super-Yang-Mills theory at six and seven loops,JHEP 08(2019) 016 [1903.10890]
-
[27]
B. Basso, L.J. Dixon and A.G. Tumanov,The three-point form factor of Trϕ 3 to six loops, JHEP02(2025) 034 [2410.22402]
- [28]
-
[29]
L.F. Alday and J.M. Maldacena,Gluon scattering amplitudes at strong coupling,JHEP06 (2007) 064 [0705.0303]
-
[30]
J.M. Drummond, G.P. Korchemsky and E. Sokatchev,Conformal properties of four-gluon planar amplitudes and Wilson loops,Nucl. Phys. B795(2008) 385 [0707.0243]
-
[31]
A. Brandhuber, P. Heslop and G. Travaglini,MHV amplitudes in N=4 super Yang-Mills and Wilson loops,Nucl. Phys. B794(2008) 231 [0707.1153]. – 44 –
-
[32]
J.M. Drummond, J. Henn, G.P. Korchemsky and E. Sokatchev,Conformal Ward identities for Wilson loops and a test of the duality with gluon amplitudes,Nucl. Phys. B826(2010) 337 [0712.1223]
-
[33]
L.F. Alday and R. Roiban,Scattering Amplitudes, Wilson Loops and the String/Gauge Theory Correspondence,Phys. Rept.468(2008) 153 [0807.1889]
- [34]
-
[35]
A. Brandhuber, B. Spence, G. Travaglini and G. Yang,Form Factors in N=4 Super Yang-Mills and Periodic Wilson Loops,JHEP01(2011) 134 [1011.1899]
-
[36]
L.F. Alday and J. Maldacena,Comments on gluon scattering amplitudes via AdS/CFT,JHEP 11(2007) 068 [0710.1060]
- [37]
-
[38]
J.M. Drummond, J. Henn, G.P. Korchemsky and E. Sokatchev,Hexagon Wilson loop = six-gluon MHV amplitude,Nucl. Phys. B815(2009) 142 [0803.1466]
-
[39]
J. Maldacena and A. Zhiboedov,Form factors at strong coupling via a Y-system,JHEP11 (2010) 104 [1009.1139]
-
[40]
R. Ben-Israel, A.G. Tumanov and A. Sever,Scattering amplitudes — Wilson loops duality for the first non-planar correction,JHEP08(2018) 122 [1802.09395]
-
[41]
J.M. Drummond, J. Henn, V.A. Smirnov and E. Sokatchev,Magic identities for conformal four-point integrals,JHEP01(2007) 064 [hep-th/0607160]
-
[42]
Z. Bern, J.J.M. Carrasco, H. Johansson and D.A. Kosower,Maximally supersymmetric planar Yang-Mills amplitudes at five loops,Phys. Rev. D76(2007) 125020 [0705.1864]
-
[43]
J.M. Drummond, J. Henn, G.P. Korchemsky and E. Sokatchev,Dual superconformal symmetry of scattering amplitudes in N=4 super-Yang-Mills theory,Nucl. Phys. B828(2010) 317 [0807.1095]
- [44]
- [45]
-
[46]
L.J. Dixon and C. Duhr,Antipodal self-duality of square fishnet graphs,Phys. Rev. D111 (2025) L101901 [2502.00862]
-
[47]
G. Yang,Color-kinematics duality and Sudakov form factor at five loops for N=4 supersymmetric Yang-Mills theory,Phys. Rev. Lett.117(2016) 271602 [1610.02394]
- [48]
- [49]
- [50]
- [51]
- [52]
-
[53]
K. Costello and N.M. Paquette,Celestial holography meets twisted holography: 4d amplitudes from chiral correlators,JHEP10(2022) 193 [2201.02595]
-
[54]
K. Costello and N.M. Paquette,Associativity of One-Loop Corrections to the Celestial Operator Product Expansion,Phys. Rev. Lett.129(2022) 231604 [2204.05301]
-
[55]
Costello,Bootstrapping two-loop QCD amplitudes,2302.00770
K.J. Costello,Bootstrapping two-loop QCD amplitudes,2302.00770
-
[56]
Morales,Two-loop QCD Amplitudes from the Chiral Algebra Bootstrap, arXiv:2510.20156
A. Morales,Two-loop QCD Amplitudes from the Chiral Algebra Bootstrap,2510.20156
-
[57]
Costello,Quantizing local holomorphic field theories on twistor space,2111.08879
K.J. Costello,Quantizing local holomorphic field theories on twistor space,2111.08879
-
[58]
V.E. Fern´ andez and N.M. Paquette,Associativity is enough: an all-orders 2d chiral algebra for 4d form factors,2412.17168
-
[59]
Perturbative gauge theory as a string theory in twistor space,
E. Witten,Perturbative gauge theory as a string theory in twistor space,Commun. Math. Phys. 252(2004) 189 [hep-th/0312171]
-
[60]
R. Boels, L.J. Mason and D. Skinner,Supersymmetric Gauge Theories in Twistor Space,JHEP 02(2007) 014 [hep-th/0604040]
-
[61]
L.J. Mason,Twistor actions for non-self-dual fields: A Derivation of twistor-string theory, JHEP10(2005) 009 [hep-th/0507269]
-
[62]
K. Costello and N.M. Paquette,Twisted Supergravity and Koszul Duality: A case study in AdS3,Commun. Math. Phys.384(2021) 279 [2001.02177]
-
[63]
N.M. Paquette and B.R. Williams,Koszul duality in quantum field theory.,Confluentes Math. 14(2023) 87 [2110.10257]
-
[64]
R. Bittleston,On the associativity of 1-loop corrections to the celestial operator product in gravity,JHEP01(2023) 018 [2211.06417]
-
[65]
Tropper,Symmetries of the Celestial Supersphere,2412.13113
A. Tropper,Symmetries of the Celestial Supersphere,2412.13113
-
[66]
A. Guevara, E. Himwich, M. Pate and A. Strominger,Holographic symmetry algebras for gauge theory and gravity,JHEP11(2021) 152 [2103.03961]
-
[67]
Strominger,w 1+∞ Algebra and the Celestial Sphere: Infinite Towers of Soft Graviton, Photon, and Gluon Symmetries,Phys
A. Strominger,w 1+∞ Algebra and the Celestial Sphere: Infinite Towers of Soft Graviton, Photon, and Gluon Symmetries,Phys. Rev. Lett.127(2021) 221601
2021
-
[68]
V.E. Fern´ andez, N.M. Paquette and B.R. Williams,Twisted holography on AdS 3 ×S 3 ×K3& the planar chiral algebra,2404.14318
-
[69]
N. Garner and N.M. Paquette,Scattering off of twistorial line defects,JHEP05(2025) 228 [2408.11092]
-
[70]
V.E. Fern´ andez,One-loop corrections to the celestial chiral algebra from Koszul Duality,JHEP 04(2023) 124 [2302.14292]. – 46 –
-
[71]
H. Jiang,Holographic chiral algebra: supersymmetry, infinite Ward identities, and EFTs,JHEP 01(2022) 113 [2108.08799]
-
[72]
Jiang,Celestial superamplitude inN= 4 SYM theory,JHEP08(2021) 031 [2105.10269]
H. Jiang,Celestial superamplitude inN= 4 SYM theory,JHEP08(2021) 031 [2105.10269]
-
[73]
Zeng,Twisted Holography and Celestial Holography from Boundary Chiral Algebra, 2302.06693
K. Zeng,Twisted Holography and Celestial Holography from Boundary Chiral Algebra, 2302.06693
- [74]
-
[75]
L. Koster,Form factors and correlation functions in N = 4 super Yang-Mills theory from twistor space, Ph.D. thesis, Humboldt U., Berlin, Inst. Math., 2017.1712.07566
-
[76]
L.J. Dixon and A. Morales,On gauge amplitudes first appearing at two loops,JHEP08(2024) 129 [2407.13967]
-
[77]
Grisaru, H.N
M.T. Grisaru, H.N. Pendleton and P. van Nieuwenhuizen,Supergravity and the S Matrix,Phys. Rev. D15(1977) 996
1977
-
[78]
Grisaru and H.N
M.T. Grisaru and H.N. Pendleton,Some Properties of Scattering Amplitudes in Supersymmetric Theories,Nucl. Phys. B124(1977) 81
1977
-
[79]
Parke and T.R
S.J. Parke and T.R. Taylor,Perturbative QCD Utilizing Extended Supersymmetry,Phys. Lett. B157(1985) 81
1985
-
[80]
Kunszt,Combined use of the CALKUL method and N = 1 supersymmetry to calculate QCD six-parton processes,Nucl
Z. Kunszt,Combined use of the CALKUL method and N = 1 supersymmetry to calculate QCD six-parton processes,Nucl. Phys. B271(1986) 333
1986
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.