Short-distance constraints for the HLbL contribution to the muon anomalous magnetic moment

Bijnens, Johan; Hermansson-Truedsson, Nils; Rodríguez-Sánchez, Antonio

doi:10.1016/j.physletb.2019.134994

Cited by 306 publications

(182 citation statements)

References 68 publications

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“…In the future, the matching to pQCD could be improved if explicit calculations of pQCD corrections became available, a first step in this direction was already taken in ref. [61]. Moreover, the phenomenological analysis would profit from further experimental information on the two-photon physics of hadronic resonances in the 1-2 GeV region, which holds true not only for the longitudinal amplitudes but in general.…”

Section: Discussionmentioning

confidence: 99%

“…In close analogy to HVP, where perturbative QCD (pQCD) becomes applicable in the high-energy tail of the dispersive integral, such constraints arise from the OPE and pQCD. In the regime where all three virtualities are large it was shown recently [61] that the pQCD quark loop indeed arises as the first term in a controlled OPE, with the next order suppressed by small quark masses and condensates. For the case in which one virtuality remains small, the leading OPE constraint was derived in ref.…”

Section: Contentsmentioning

confidence: 95%

“…[62], but was only demonstrated recently in ref. [61], by working out the next order in the expansion. While at leading order all quark masses can simply be put to zero, this is no longer true at subleading orders.…”

Section: Ope For the Asymptotic Regionmentioning

confidence: 99%

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Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2)μ with large-Nc Regge models

Colangelo

Hagelstein

Hoferichter

et al. 2020

J. High Energ. Phys.

285

166

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While the low-energy part of the hadronic light-by-light (HLbL) tensor can be constrained from data using dispersion relations, for a full evaluation of its contribution to the anomalous magnetic moment of the muon (g − 2) µ also mixed-and high-energy regions need to be estimated. Both can be addressed within the operator product expansion (OPE), either for configurations where all photon virtualities become large or one of them remains finite. Imposing such short-distance constraints (SDCs) on the HLbL tensor is thus a major aspect of a model-independent approach towards HLbL scattering. Here, we focus on longitudinal SDCs, which concern the amplitudes containing the pseudoscalar-pole contributions from π 0 , η, η . Since these conditions cannot be fulfilled by a finite number of pseudoscalar poles, we consider a tower of excited pseudoscalars, constraining their masses and transition form factors from Regge theory, the OPE, and phenomenology. Implementing a matching of the resulting expressions for the HLbL tensor onto the perturbative QCD quark loop, we are able to further constrain our calculation and significantly reduce its model dependence. We find that especially for the π 0 the corresponding increase of the HLbL contribution is much smaller than previous prescriptions in the literature would imply. Overall, we estimate that longitudinal SDCs increase the HLbL contribution by ∆a LSDC µ = 13(6) × 10 −11 . A Anomalous Pseudoscalar-Vector-Vector Coupling 46 B Alternative model for pion, η, and η transition form factors 48 1 Introduction Current Standard Model (SM) evaluations of the anomalous magnetic moment of the muon, a µ = (g − 2) µ /2, differ from the value measured at the Brookhaven National Laboratory [1]a exp µ = 116 592 089(63) × 10 −11 , (1.1) by around 3.5 σ. In the near future, the new Fermilab E989 experiment [2] will be able to reduce the experimental uncertainty by a factor 4, and the E34 experiment at J-PARC [3] will provide an important cross check, see ref.[4] for a comparison of the experimental methods. Therefore, the theoretical calculation of a µ needs to be improved accordingly. The uncertainty of the SM prediction mainly stems from hadronic contributions, such as hadronic vacuum polarization (HVP), see figure 1 (a), and HLbL scattering, see figure 1 (b). Since the HVP contribution can be systematically calculated with a data-driven dispersive approach [5-9], lattice QCD [10][11][12][13][14][15][16], and potentially be accessed independently by the proposed MUonE experiment [17,18], which aims to measure the space-like finestructure constant α(t) in elastic electron-muon scattering, the HLbL contribution may end up dominating the theoretical error. 1 Apart from lattice QCD [27][28][29], recent data-driven approaches towards HLbL scattering are again rooted in dispersion theory, either for the HLbL tensor [30][31][32][33][34][35], the Pauli 1 Note that higher-order insertions of HVP [5,19,20] and HLbL [21] are already under sufficient control, as are hadronic corrections in the anomalou...

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Section: Discussionmentioning

confidence: 99%

Section: Contentsmentioning

confidence: 95%

See 1 more Smart Citation

Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2)μ with large-Nc Regge models

Colangelo

Hagelstein

Hoferichter

et al. 2020

J. High Energ. Phys.

285

166

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“…In the limit where all Q 2 i are large, the calculation from [43] establishes the pQCD quark loop as the first term in a systematic OPE. In particular, this implies the constraint…”

Section: Ope Constraints On Hlbl Scatteringmentioning

confidence: 99%

“…Recently, it was shown that the former situation can be addressed in a systematic operator product expansion (OPE), in which the pQCD quark loop emerges as the first term in the expansion [43]. The second configuration is related to so-called mixed regions in the g − 2 integral, i.e., integration regions in which asymptotic arguments only apply to a subset of arXiv:1910.11881v1 [hep-ph] 25 Oct 2019 the kinematic variables, while hadronic physics may still be relevant for others.…”

Section: Introductionmentioning

confidence: 99%

Short-distance constraints on hadronic light-by-light scattering in the anomalous magnetic moment of the muon

et al. 2020

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A key ingredient in the evaluation of hadronic light-by-light (HLbL) scattering in the anomalous magnetic moment of the muon (g − 2)µ concerns short-distance constraints (SDCs) that follow from QCD by means of the operator product expansion. Here we concentrate on the most important such constraint, in the longitudinal amplitudes, and show that it can be implemented efficiently in terms of a Regge sum over excited pseudoscalar states, constrained by phenomenological input on masses, two-photon couplings, as well as SDCs on HLbL scattering and the pseudoscalar transition form factors (TFFs). Our estimate of the effect of the longitudinal SDCs on the HLbL contribution is: ∆a LSDC µ = 13(6) × 10 −11 . This is significantly smaller than previous estimates, which mostly relied on an ad-hoc modification of the pseudoscalar poles and led to up to a 40% increase with respect to the nominal pseudoscalar-pole contributions, when evaluated with modern input for the relevant TFFs. We also comment on the status of the transversal SDCs and, by matching to perturbative QCD, argue that the corresponding correction will be significantly smaller than its longitudinal counterpart.

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The tiny (g-2) muon wobble from small-μ supersymmetry

Baum

Carena

Shah

et al. 2022

J. High Energ. Phys.

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A new measurement of the muon anomalous magnetic moment, gμ− 2, has been reported by the Fermilab Muon g-2 collaboration and shows a 4.2 σ departure from the most precise and reliable calculation of this quantity in the Standard Model. Assuming that this discrepancy is due to new physics, we concentrate on a simple supersymmetric model that also provides a dark matter explanation in a previously unexplored region of supersymmetric parameter space. Such interesting region can realize a Bino-like dark matter candidate compatible with all current direct detection constraints for small to moderate values of the Higgsino mass parameter |μ|. This in turn would imply the existence of light additional Higgs bosons and Higgsino particles within reach of the high-luminosity LHC and future colliders. We provide benchmark scenarios that will be tested in the next generation of direct dark matter experiments and at the LHC.

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Short-distance constraints for the HLbL contribution to the muon anomalous magnetic moment

Cited by 306 publications

References 68 publications

Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2)μ with large-Nc Regge models

Longitudinal short-distance constraints for the hadronic light-by-light contribution to (g − 2)μ with large-Nc Regge models

Short-distance constraints on hadronic light-by-light scattering in the anomalous magnetic moment of the muon

The tiny (g-2) muon wobble from small-μ supersymmetry

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