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Lattice calculation of the π0, η and η transition form factors and the hadronic light-by-light contribution to the muon g2

Antoine Gérardin1,*, Willem E. A. Verplanke1,†, Gen Wang1, Zoltan Fodor2,3,4,5, Jana N. Guenther2, Laurent Lellouch1, Kalman K. Szabo2,3, and Lukas Varnhorst2

  • *Contact author: antoine.gerardin@cpt.univ-mrs.fr
  • Contact author: willem.verplanke@cpt.univ-mrs.fr

Phys. Rev. D 111, 054511 – Published 21 March, 2025

DOI: https://doi.org/10.1103/PhysRevD.111.054511

Abstract

In this paper we present a first ab initio calculation of the π0, η and η transition form factors performed with physical light-quark masses. We provide a complete parametrization of the form factors that includes both single and double-virtual kinematics. Our results are compared with experimental measurements of the form factors in the spacelike region and with the measured two-photon decay widths. In a second step, our parametrizations of the transition form factors are used to compute the dominant pseudoscalar-pole contributions to the hadronic light-by-light scattering in the muon g2. Our final result reads aμhlbl,ps-pole=(85.1±5.2)×1011. Although the pion-pole is dominant, we confirm that, together, the η and η provide roughly half of its contribution.

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References (110)

  1. B. Abi et al. (Muon g2 Collaboration), Measurement of the positive muon anomalous magnetic moment to 0.46 ppm, Phys. Rev. Lett. 126, 141801 (2021).
  2. G. W. Bennett et al. (Muon g2 Collaboration), Final report of the muon E821 anomalous magnetic moment measurement at BNL, Phys. Rev. D 73, 072003 (2006).
  3. T. Aoyama et al., The anomalous magnetic moment of the muon in the standard model, Phys. Rep. 887, 1 (2020).
  4. J. Grange et al. (Muon g2Collaboration), Muon (g-2) technical design report, arXiv:1501.06858.
  5. M. Abe et al., A new approach for measuring the muon anomalous magnetic moment and electric dipole moment, Prog. Theor. Exp. Phys. 2019, 053C02 (2019).
  6. M. Della Morte, A. Francis, V. Gülpers, G. Herdoíza, G. von Hippel, H. Horch, B. Jäger, H. B. Meyer, A. Nyffeler, and H. Wittig, The hadronic vacuum polarization contribution to the muon g2 from lattice QCD, J. High Energy Phys. 10 (2017) 020.
  7. B. Chakraborty et al. (Fermilab Lattice, LATTICE-HPQCD, and MILC Collaborations), Strong-isospin-breaking correction to the muon anomalous magnetic moment from lattice QCD at the physical point, Phys. Rev. Lett. 120, 152001 (2018).
  8. S. Borsanyi et al. (Budapest-Marseille-Wuppertal Collaboration), Hadronic vacuum polarization contribution to the anomalous magnetic moments of leptons from first principles, Phys. Rev. Lett. 121, 022002 (2018).
  9. T. Blum, P. A. Boyle, V. Gülpers, T. Izubuchi, L. Jin, C. Jung, A. Jüttner, C. Lehner, A. Portelli, and J. T. Tsang (RBC and UKQCD Collaborations), Calculation of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment, Phys. Rev. Lett. 121, 022003 (2018).
  10. D. Giusti, V. Lubicz, G. Martinelli, F. Sanfilippo, and S. Simula, Electromagnetic and strong isospin-breaking corrections to the muon g2 from lattice QCD+QED, Phys. Rev. D 99, 114502 (2019).
  11. E. Shintani and Y. Kuramashi (PACS Collaboration), Hadronic vacuum polarization contribution to the muon g2 with 2+1 flavor lattice QCD on a larger than (10fm)4 lattice at the physical point, Phys. Rev. D 100, 034517 (2019).
  12. C. T. H. Davies et al. (Fermilab Lattice, LATTICE-HPQCD, and MILC Collaborations), Hadronic-vacuum-polarization contribution to the muon’s anomalous magnetic moment from four-flavor lattice QCD, Phys. Rev. D 101, 034512 (2020).
  13. A. Gérardin, M. Cè, G. von Hippel, B. Hörz, H. B. Meyer, D. Mohler, K. Ottnad, J. Wilhelm, and H. Wittig, The leading hadronic contribution to (g2)μ from lattice QCD with Nf=2+1 flavours of O(a) improved Wilson quarks, Phys. Rev. D 100, 014510 (2019).
  14. C. Aubin, T. Blum, C. Tu, M. Golterman, C. Jung, and S. Peris, Light quark vacuum polarization at the physical point and contribution to the muon g2, Phys. Rev. D 101, 014503 (2020).
  15. D. Giusti and S. Simula, Lepton anomalous magnetic moments in lattice QCD+QED, Proc. Sci. LATTICE2019 (2019) 104 [arXiv:1910.03874].
  16. S. Borsanyi et al., Leading hadronic contribution to the muon magnetic moment from lattice QCD, Nature (London) 593, 51 (2021).
  17. C. Lehner and A. S. Meyer, Consistency of hadronic vacuum polarization between lattice QCD and the r-ratio, Phys. Rev. D 101, 074515 (2020).
  18. D. Giusti and S. Simula, Window contributions to the muon hadronic vacuum polarization with twisted-mass fermions, Proc. Sci. LATTICE2021 (2022) 189 [arXiv:2111.15329].
  19. G. Wang, T. Draper, K.-F. Liu, and Y.-B. Yang (χQCD Collaboration), Muon g-2 with overlap valence fermion, arXiv:2204.01280.
  20. C. Aubin, T. Blum, M. Golterman, and S. Peris, Muon anomalous magnetic moment with staggered fermions: Is the lattice spacing small enough?, Phys. Rev. D 106, 054503 (2022).
  21. M. Davier, A. Hoecker, B. Malaescu, and Z. Zhang, Reevaluation of the hadronic vacuum polarisation contributions to the Standard Model predictions of the muon g2 and α(mZ2) using newest hadronic cross-section data, Eur. Phys. J. C 77, 827 (2017).
  22. A. Keshavarzi, D. Nomura, and T. Teubner, Muon g2 and α(MZ2): A new data-based analysis, Phys. Rev. D 97, 114025 (2018).
  23. G. Colangelo, M. Hoferichter, and P. Stoffer, Two-pion contribution to hadronic vacuum polarization, J. High Energy Phys. 02 (2019) 006.
  24. M. Hoferichter, B.-L. Hoid, and B. Kubis, Three-pion contribution to hadronic vacuum polarization, J. High Energy Phys. 08 (2019) 137.
  25. M. Davier, A. Hoecker, B. Malaescu, and Z. Zhang, A new evaluation of the hadronic vacuum polarisation contributions to the muon anomalous magnetic moment and to α(mZ2), Eur. Phys. J. C 80, 241 (2020); 80, 410(E) (2020).
  26. A. Keshavarzi, D. Nomura, and T. Teubner, The g2 of charged leptons, α(MZ2) and the hyperfine splitting of muonium, Phys. Rev. D 101, 014029 (2020).
  27. G. Colangelo, M. Hoferichter, and P. Stoffer, Constraints on the two-pion contribution to hadronic vacuum polarization, Phys. Lett. B 814, 136073 (2021).
  28. A. Crivellin, M. Hoferichter, C. A. Manzari, and M. Montull, Hadronic vacuum polarization: (g2)μ versus global electroweak fits, Phys. Rev. Lett. 125, 091801 (2020).
  29. A. Keshavarzi, W. J. Marciano, M. Passera, and A. Sirlin, Muon g2 and Δα connection, Phys. Rev. D 102, 033002 (2020).
  30. B. Malaescu and M. Schott, Impact of correlations between aμ and αQED on the EW fit, Eur. Phys. J. C 81, 46 (2021).
  31. T. Blum, S. Chowdhury, M. Hayakawa, and T. Izubuchi, Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment from lattice QCD, Phys. Rev. Lett. 114, 012001 (2015).
  32. T. Blum, N. Christ, M. Hayakawa, T. Izubuchi, L. Jin, and C. Lehner, Lattice calculation of hadronic Light-by-Light contribution to the muon anomalous magnetic moment, Phys. Rev. D 93, 014503 (2016).
  33. T. Blum, N. Christ, M. Hayakawa, T. Izubuchi, L. Jin, C. Jung, and C. Lehner, Connected and leading disconnected hadronic light-by-light contribution to the muon anomalous magnetic moment with a physical pion mass, Phys. Rev. Lett. 118, 022005 (2017).
  34. T. Blum, N. Christ, M. Hayakawa, T. Izubuchi, L. Jin, C. Jung, and C. Lehner, Hadronic light-by-light scattering contribution to the muon anomalous magnetic moment from lattice QCD, Phys. Rev. Lett. 124, 132002 (2020).
  35. T. Blum, N. Christ, M. Hayakawa, T. Izubuchi, L. Jin, C. Jung, C. Lehner, and C. Tu, Hadronic light-by-light contribution to the muon anomaly from lattice QCD with infinite volume QED at physical pion mass, Phys. Rev. D 111, 014501 (2025).
  36. J. Green, O. Gryniuk, G. von Hippel, H. B. Meyer, and V. Pascalutsa, Lattice QCD calculation of hadronic light-by-light scattering, Phys. Rev. Lett. 115, 222003 (2015).
  37. J. Green, N. Asmussen, O. Gryniuk, G. von Hippel, H. B. Meyer, A. Nyffeler, and V. Pascalutsa, Direct calculation of hadronic light-by-light scattering, Proc. Sci. LATTICE2015 (2016) 109 [arXiv:1510.08384].
  38. A. Gérardin, J. Green, O. Gryniuk, G. von Hippel, H. B. Meyer, V. Pascalutsa, and H. Wittig, Hadronic light-by-light scattering amplitudes from lattice QCD versus dispersive sum rules, Phys. Rev. D 98, 074501 (2018).
  39. E.-H. Chao, A. Gérardin, J. R. Green, R. J. Hudspith, and H. B. Meyer, Hadronic light-by-light contribution to (g2)μ from lattice QCD with SU(3) flavor symmetry, Eur. Phys. J. C 80, 869 (2020).
  40. E.-H. Chao, R. J. Hudspith, A. Gérardin, J. R. Green, H. B. Meyer, and K. Ottnad, Hadronic light-by-light contribution to (g2)μ from lattice QCD: A complete calculation, Eur. Phys. J. C 81, 651 (2021).
  41. N. Asmussen, E.-H. Chao, A. Gérardin, J. R. Green, R. J. Hudspith, H. B. Meyer, and A. Nyffeler, Hadronic light-by-light scattering contribution to the muon g2 from lattice QCD: Semi-analytical calculation of the QED kernel, J. High Energy Phys. 04 (2023) 040.
  42. E.-H. Chao, R. J. Hudspith, A. Gérardin, J. R. Green, and H. B. Meyer, The charm-quark contribution to light-by-light scattering in the muon (g2) from lattice QCD, Eur. Phys. J. C 82, 664 (2022).
  43. G. Colangelo, M. Hoferichter, M. Procura, and P. Stoffer, Dispersive approach to hadronic light-by-light scattering, J. High Energy Phys. 09 (2014) 091.
  44. G. Colangelo, M. Hoferichter, B. Kubis, M. Procura, and P. Stoffer, Towards a data-driven analysis of hadronic light-by-light scattering, Phys. Lett. B 738, 6 (2014).
  45. G. Colangelo, M. Hoferichter, M. Procura, and P. Stoffer, Dispersion relation for hadronic light-by-light scattering: Theoretical foundations, J. High Energy Phys. 09 (2015) 074.
  46. G. Colangelo, M. Hoferichter, M. Procura, and P. Stoffer, Rescattering effects in the hadronic-light-by-light contribution to the anomalous magnetic moment of the muon, Phys. Rev. Lett. 118, 232001 (2017).
  47. G. Colangelo, M. Hoferichter, M. Procura, and P. Stoffer, Dispersion relation for hadronic light-by-light scattering: Two-pion contributions, J. High Energy Phys. 04 (2017) 161.
  48. E.-H. Chao, R. J. Hudspith, A. Gérardin, J. R. Green, H. B. Meyer, and K. Ottnad, Hadronic light-by-light contribution to (g2)μ from lattice QCD: A complete calculation, Proc. Sci. LATTICE2021 (2022) 209.
  49. B. Aubert et al. (BABAR Collaboration), Measurement of the γγ*π0 transition form factor, Phys. Rev. D 80, 052002 (2009).
  50. H. J. Behrend et al. (CELLO Collaboration), A measurement of the π0, η and η electromagnetic form-factors, Z. Phys. C 49, 401 (1991).
  51. J. Gronberg et al. (CLEO Collaboration), Measurements of the meson—photon transition form-factors of light pseudoscalar mesons at large momentum transfer, Phys. Rev. D 57, 33 (1998).
  52. S. Uehara et al. (Belle Collaboration), Measurement of γγ*π0 transition form factor at Belle, Phys. Rev. D 86, 092007 (2012).
  53. P. del Amo Sanchez et al. (BABAR Collaboration), Measurement of the γγ*η and γγ*η transition form factors, Phys. Rev. D 84, 052001 (2011).
  54. M. Acciarri et al. (L3 Collaboration), Measurement of η (958) formation in two photon collisions at LEP-1, Phys. Lett. B 418, 399 (1998).
  55. J. P. Lees et al. (BABAR Collaboration), Measurement of the γγη transition form factor, Phys. Rev. D 98, 112002 (2018).
  56. M. Tanabashi et al. (Particle Data Group), Review of particle physics, Phys. Rev. D 98, 030001 (2018).
  57. I. Larin et al. (PrimEx-II Collaboration), Precision measurement of the neutral pion lifetime, Science 368, 506 (2020).
  58. A. Gérardin, H. B. Meyer, and A. Nyffeler, Lattice calculation of the pion transition form factor π0γ*γ*, Phys. Rev. D 94, 074507 (2016).
  59. A. Gérardin, H. B. Meyer, and A. Nyffeler, Lattice calculation of the pion transition form factor with Nf=2+1 Wilson quarks, Phys. Rev. D 100, 034520 (2019).
  60. M. Hoferichter, B.-L. Hoid, B. Kubis, S. Leupold, and S. P. Schneider, Dispersion relation for hadronic light-by-light scattering: Pion pole, J. High Energy Phys. 10 (2018) 141.
  61. M. Hoferichter, B.-L. Hoid, B. Kubis, S. Leupold, and S. P. Schneider, Pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon, Phys. Rev. Lett. 121, 112002 (2018).
  62. C. Alexandrou et al., The ηγ*γ* transition form factor and the hadronic light-by-light η-pole contribution to the muon g2 from lattice QCD, Phys. Rev. D 108, 054509 (2023).
  63. W. E. A. Verplanke, Z. Fodor, A. Gerardin, J. N. Guenther, L. Lellouch, K. K. Szabo, B. C. Toth, and L. Varnhorst, Lattice QCD calculation of the η and η meson masses at the physical point using rooted staggered fermions, arXiv:2409.18846.
  64. X.-d. Ji and C.-w. Jung, Studying hadronic structure of the photon in lattice QCD, Phys. Rev. Lett. 86, 208 (2001).
  65. X.-d. Ji and C.-w. Jung, Photon structure functions from quenched lattice QCD, Phys. Rev. D 64, 034506 (2001).
  66. B. Blossier, M. Della Morte, G. von Hippel, T. Mendes, and R. Sommer, On the generalized eigenvalue method for energies and matrix elements in lattice field theory, J. High Energy Phys. 04 (2009) 094.
  67. F. Jegerlehner and A. Nyffeler, The muon g-2, Phys. Rep. 477, 1 (2009).
  68. S. R. Sharpe, Rooted staggered fermions: Good, bad or ugly?, Proc. Sci. LAT2006 (2006) 022 [arXiv:hep-lat/0610094].
  69. M. Creutz, Why rooting fails, Proc. Sci. LATTICE2007 (2007) 007 [arXiv:0708.1295].
  70. M. Creutz, Chiral anomalies and rooted staggered fermions, Phys. Lett. B 649, 230 (2007).
  71. C. Bernard, Staggered chiral perturbation theory and the fourth-root trick, Phys. Rev. D 73, 114503 (2006).
  72. A. S. Kronfeld, Lattice gauge theory with staggered fermions: How, where, and why (not), Proc. Sci. LATTICE2007 (2007) 016 [arXiv:0711.0699].
  73. M. Golterman, QCD with rooted staggered fermions, Proc. Sci. CONFINEMENT8 (2008) 014 [arXiv:0812.3110].
  74. D. H. Adams, The rooting issue for a lattice fermion formulation similar to staggered fermions but without taste mixing, Phys. Rev. D 77, 105024 (2008).
  75. E. Follana, Q. Mason, C. Davies, K. Hornbostel, G. P. Lepage, J. Shigemitsu, H. Trottier, and K. Wong (HPQCD and UKQCD Collaborations), Highly improved staggered quarks on the lattice, with applications to charm physics, Phys. Rev. D 75, 054502 (2007).
  76. R. Altmeyer, K. D. Born, M. Gockeler, R. Horsley, E. Laermann, and G. Schierholz (MT(c) Collaboration), The hadron spectrum in QCD with dynamical staggered fermions, Nucl. Phys. B389, 445 (1993).
  77. P. Lepage, Perturbative improvement for lattice QCD: An update, Nucl. Phys. B, Proc. Suppl. 60, 267 (1998).
  78. G. P. Lepage, Flavor symmetry restoration and Symanzik improvement for staggered quarks, Phys. Rev. D 59, 074502 (1999).
  79. T. A. DeGrand and S. Schaefer, Improving meson two-point functions by low-mode averaging, Nucl. Phys. B, Proc. Suppl. 140, 296 (2005).
  80. L. Giusti, P. Hernandez, M. Laine, P. Weisz, and H. Wittig, Low-energy couplings of QCD from current correlators near the chiral limit, J. High Energy Phys. 04 (2004) 013.
  81. G. S. Bali, S. Collins, and A. Schafer, Effective noise reduction techniques for disconnected loops in lattice QCD, Comput. Phys. Commun. 181, 1570 (2010).
  82. T. Blum, T. Izubuchi, and E. Shintani, New class of variance-reduction techniques using lattice symmetries, Phys. Rev. D 88, 094503 (2013).
  83. E. Shintani, R. Arthur, T. Blum, T. Izubuchi, C. Jung, and C. Lehner, Covariant approximation averaging, Phys. Rev. D 91, 114511 (2015).
  84. E. B. Gregory, A. C. Irving, C. M. Richards, and C. McNeile, Methods for pseudoscalar flavour-singlet mesons with staggered fermions, Phys. Rev. D 77, 065019 (2008).
  85. L. Giusti, T. Harris, A. Nada, and S. Schaefer, Frequency-splitting estimators of single-propagator traces, Eur. Phys. J. C 79, 586 (2019).
  86. X. Feng, S. Aoki, H. Fukaya, S. Hashimoto, T. Kaneko, J.-i. Noaki, and E. Shintani, Two-photon decay of the neutral pion in lattice QCD, Phys. Rev. Lett. 109, 182001 (2012).
  87. C. G. Boyd, B. Grinstein, and R. F. Lebed, Model independent determinations of B¯Dν¯, D*ν¯ form-factors, Nucl. Phys. B461, 493 (1996).
  88. G. P. Lepage and S. J. Brodsky, Exclusive processes in quantum chromodynamics: Evolution equations for hadronic wave functions and the form-factors of mesons, Phys. Lett. B 87, 359 (1979).
  89. G. P. Lepage and S. J. Brodsky, Exclusive processes in perturbative quantum chromodynamics, Phys. Rev. D 22, 2157 (1980).
  90. S. J. Brodsky and G. P. Lepage, Large angle two photon exclusive channels in quantum chromodynamics, Phys. Rev. D 24, 1808 (1981).
  91. V. A. Nesterenko and A. V. Radyushkin, Comparison of the QCD sum rule approach and perturbative QCD analysis for γ*γ*π0 process, Sov. J. Nucl. Phys. 38, 284 (1983), https://inspirehep.net/literature/182367.
  92. V. A. Novikov, M. A. Shifman, A. I. Vainshtein, M. B. Voloshin, and V. I. Zakharov, Use and misuse of QCD sum rules, factorization and related topics, Nucl. Phys. B237, 525 (1984).
  93. M. Ammer and S. Durr, Details of a staggered fermion data analysis, Proc. Sci. LATTICE2019 (2020) 048 [arXiv:1910.11046].
  94. M. Bruno and R. Sommer, On fits to correlated and auto-correlated data, Comput. Phys. Commun. 285, 108643 (2023).
  95. P. Masjuan and P. Sanchez-Puertas, Pseudoscalar-pole contribution to the (gμ2): A rational approach, Phys. Rev. D 95, 054026 (2017).
  96. G. Eichmann, C. S. Fischer, E. Weil, and R. Williams, Single pseudoscalar meson pole and pion box contributions to the anomalous magnetic moment of the muon, Phys. Lett. B 797, 134855 (2019); 799, 135029(E) (2019).
  97. I. Larin et al. (PrimEx Collaboration), A new measurement of the π0 radiative decay width, Phys. Rev. Lett. 106, 162303 (2011).
  98. R. L. Workman et al. (Particle Data Group), Review of particle physics, Prog. Theor. Exp. Phys. 2022, 083C01 (2022).
  99. A. Browman, J. DeWire, B. Gittelman, K. M. Hanson, E. Loh, and R. Lewis, The radiative width of the η meson, Phys. Rev. Lett. 32, 1067 (1974).
  100. W. Bartel et al. (JADE Collaboration), A measurement of the η radiative width Γηγγ, Phys. Lett. B 158, 511 (1985).
  101. D. Williams et al. (Crystal Ball Collaboration), Formation of the pseudoscalars π0, η and η in the reaction γγγγ, Phys. Rev. D 38, 1365 (1988).
  102. N. A. Roe et al., A measurement of the radiative width of the η and η mesons with the asp detector, Phys. Rev. D 41, 17 (1990).
  103. S. E. Baru et al., Measurement of two photon widths of the A2, η, η, Z. Phys. C 48, 581 (1990).
  104. D. Babusci et al. (KLOE-2 Collaboration), Measurement of η meson production in γγ interactions and Γ(ηγγ) with the KLOE detector, J. High Energy Phys. 01 (2013) 119.
  105. Liping Gan, The η and η physics at JLab, in Fifth Plenary Workshop of the Muon g–2 Theory Initiative (2022), https://indico.ph.ed.ac.uk/event/112/timetable/?view=standard_numbered.
  106. A. Nyffeler, Precision of a data-driven estimate of hadronic light-by-light scattering in the muon g2: Pseudoscalar-pole contribution, Phys. Rev. D 94, 053006 (2016).
  107. K. Raya, A. Bashir, and P. Roig, Contribution of neutral pseudoscalar mesons to aμHLbL within a Schwinger-Dyson equations approach to QCD, Phys. Rev. D 101, 074021 (2020).
  108. Y. Meng, X. Feng, C. Liu, T. Wang, and Z. Zou, First-principle calculation of ηc2γ decay width from lattice QCD, Sci. Bull. 68, 1880 (2023).
  109. X. Feng and L. Jin, QED self energies from lattice QCD without power-law finite-volume errors, Phys. Rev. D 100, 094509 (2019).
  110. V. Gülpers, A. Francis, B. Jäger, H. Meyer, G. von Hippel, and H. Wittig, The leading disconnected contribution to the anomalous magnetic moment of the muon, Proc. Sci. LATTICE2014 (2014) 128 [arXiv:1411.7592].

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