t+t clustering in He-isotopes

Aoyama, Shigeyoshi; Itagaki, N.; Arai, K.; Katō, Kiyoshi; Oi, Makito

doi:10.1142/s021773230602216x

Cited by 77 publications

(147 citation statements)

References 14 publications

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“…Adding to (6) the contributions from higher order hadronic loops, −9.87 ± 0.09 (NLO) and 1.24 ± 0.01 (NNLO) [50], hadronic light-by-light scattering, 10.5 ± 2.6 [51], as well as QED, 11 658 471.895 ± 0.008 [52] (see also [53] and references therein), and electroweak effects, 15.36 ± 0.10 [54], 10 we obtain the complete SM prediction a SM µ = 11 659 183.0 ± 4.0 ± 2.6 ± 0.1 (4.8 tot ) ,…”

Section: Muon Magnetic Anomalymentioning

confidence: 99%

A new evaluation of the hadronic vacuum polarisation contributions to the muon anomalous magnetic moment and to $$\varvec{\alpha }({{\varvec{m}}}_{{\varvec{Z}}}^2)$$

et al. 2020

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We reevaluate the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the Z-boson mass. We include newest e + e − → hadrons cross-section data together with a phenomenological fit of the threshold region in the evaluation of the dispersion integrals. The precision in the individual datasets cannot be fully exploited due to discrepancies that lead to additional systematic uncertainty in particular between BABAR and KLOE data in the dominant π + π − channel. For the muon (g − 2)/2, we find for the lowest-order hadronic contribution (693.9 ± 4.0) · 10 −10 . The full Standard Model prediction differs by 3.3σ from the experimental value. The five-quark hadronic contribution to α(m 2 Z ) is evaluated to be (276.1 ± 1.0) · 10 −4 .

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Section: Muon Magnetic Anomalymentioning

confidence: 99%

A new evaluation of the hadronic vacuum polarisation contributions to the muon anomalous magnetic moment and to $$\varvec{\alpha }({{\varvec{m}}}_{{\varvec{Z}}}^2)$$

et al. 2020

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“…C 12 [f ] := f (µ ↔ ν, q 1 ↔ q 2 ), C 14 [f ] := f (µ ↔ σ, q 1 ↔ −q 4 ), (2.9) and multiple operations are understood to act as in the example C 12 [C 23 [f (q 1 , q 2 , q 3 , q 4 )]] = C 12 [f (q 1 , q 3 , q 2 , q 4 )] = f (q 2 , q 3 , q 1 , q 4 ). In addition, theΠ i preserve the crossing symmetrieŝ…”

Section: Contentsmentioning

confidence: 99%

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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“…has resulted in a ∼ 3.7σ discrepancy [1,2] which is yet to be understood. While impressive agreement has existed between the Standard Model (SM) prediction and measurements on the electron's anomalous magnetic moment a e [3], a recent improvement in the determination of the fine structure constant α from atomic Cesium measurements [4] has pushed the discrepancy in ∆a e from ∼ 1.7σ to ∼ 2.4σ with opposite sign to that of the muon [5-7] 1 .…”

Section: Introductionmentioning

confidence: 99%

Revisiting the dark photon explanation of the muon anomalous magnetic moment

Mohlabeng

2019

Phys. Rev. D

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A massive U (1) gauge boson known as a "dark photon" or A , has long been proposed as a potential explanation for the discrepancy observed between the experimental measurement and theoretical determination of the anomalous magnetic moment of the muon (gµ − 2) anomaly. Recently, experimental results have excluded this possibility for a dark photon exhibiting exclusively visible or invisible decays. In this work, we revisit this idea and consider a model where A couples inelastically to dark matter and an excited dark sector state, leading to a more exotic decay topology we refer to as a semi-visible decay. We show that for large mass splittings between the dark sector states this decay mode is enhanced, weakening the previous invisibly decaying dark photon bounds. As a consequence, A resolves the gµ − 2 anomaly in a region of parameter space the thermal dark matter component of the Universe is readily explained. Interestingly, it is possible that the semi-visible events we discuss may have been vetoed by experiments searching for invisible dark photon decays. A re-analysis of the data and future searches may be crucial in uncovering this exotic decay mode or closing the window on the dark photon explanation of the gµ − 2 anomaly.

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t+t clustering in He-isotopes

Cited by 77 publications

References 14 publications

A new evaluation of the hadronic vacuum polarisation contributions to the muon anomalous magnetic moment and to $$\varvec{\alpha }({{\varvec{m}}}_{{\varvec{Z}}}^2)$$

A new evaluation of the hadronic vacuum polarisation contributions to the muon anomalous magnetic moment and to $$\varvec{\alpha }({{\varvec{m}}}_{{\varvec{Z}}}^2)$$

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

Revisiting the dark photon explanation of the muon anomalous magnetic moment

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