scholarly journals (g−2)µ at four loops in QED

2019 ◽  
Vol 218 ◽  
pp. 01004 ◽  
Author(s):  
Peter Marquard ◽  
Alexander V. Smirnov ◽  
Vladimir A. Smirnov ◽  
Matthias Steinhauser ◽  
David Wellmann

We review the four-loop QED corrections to the anomalous magnetic moment of the muon. The fermionic contributions with closed electron and tau contributions are discussed. Furthermore, we report on a new independent calculation of the universal four-loop contribution and compare with existing results.

2014 ◽  
Vol 35 ◽  
pp. 1460417
Author(s):  
MATTHIAS STEINHAUSER

In this contribution we present recent four-loop results for the muon anomalous magnetic moment based on analytic methods. In particular, fermionic corrections involving two or more closed electron loops or at least one tau lepton loop are discussed.


2018 ◽  
Vol 179 ◽  
pp. 01001 ◽  
Author(s):  
Johan Bijnens

This talk is about the hadronic light-by-light contribution to the muon anomalous magnetic moment, mainly our old work but including some newer results as well. It concentrates on the model calculations. Most attention is paid to pseudo-scalar exchange and the pion loop contribution. Scalar, a1-exchange and other contributions are shortly discussed as well. For the π0-exchange a possible large cancellation between connected and disconnected diagrams is expected.


2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Essodjolo Kpatcha ◽  
Iñaki Lara ◽  
Daniel E. López-Fogliani ◽  
Carlos Muñoz ◽  
Natsumi Nagata

AbstractWe analyze the anomalous magnetic moment of the muon $$g-2$$ g - 2 in the $$\mu \nu $$ μ ν SSM. This R-parity violating model solves the $$\mu $$ μ problem reproducing simultaneously neutrino data, only with the addition of right-handed neutrinos. In the framework of the $$\mu \nu $$ μ ν SSM, light left muon-sneutrino and wino masses can be naturally obtained driven by neutrino physics. This produces an increase of the dominant chargino-sneutrino loop contribution to muon $$g-2$$ g - 2 , solving the gap between the theoretical computation and the experimental data. To analyze the parameter space, we sample the $$\mu \nu $$ μ ν SSM using a likelihood data-driven method, paying special attention to reproduce the current experimental data on neutrino and Higgs physics, as well as flavor observables such as B and $$\mu $$ μ decays. We then apply the constraints from LHC searches for events with multi-leptons + MET on the viable regions found. They can probe these regions through chargino–chargino, chargino–neutralino and neutralino–neutralino pair production. We conclude that significant regions of the parameter space of the $$\mu \nu \mathrm{SSM}$$ μ ν SSM can explain muon $$g-2$$ g - 2 data.


2015 ◽  
Vol 25 (1) ◽  
pp. 29 ◽  
Author(s):  
Dinh Thanh Binh ◽  
Do Thi Huong ◽  
Le Tho Hue ◽  
Hoang Ngoc Long

We investigate in detail  $one-loop$ contribution of new particles to the muon  anomalous magnetic moment \((g-2)_\mu\) in the framework of the economical 3-3-1 model. The main contributions to the anomalous magnetic moment come from new neutral gauge boson \(Z'\),  bilepton  singly charged  vector boson $Y^\pm$. The contributions of new neutral/charged scalars are small and can be neglected. The result is extended to other versions of 3-3-1 models.Comparing the anomalous magnetic moment value in this model with experimental value we set the extension requirement for the model.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Wen Qin ◽  
Ling-Yun Dai ◽  
Jorge Portolés

Abstract A coherent study of e+e− annihilation into two (π+π−, K+K−) and three (π+π−π0, π+π−η) pseudoscalar meson production is carried out within the framework of resonance chiral theory in energy region E ≲ 2 GeV. The work of [L.Y. Dai, J. Portolés, and O. Shekhovtsova, Phys. Rev. D88 (2013) 056001] is revisited with the latest experimental data and a joint analysis of two pseudoscalar meson production. Hence, we evaluate the lowest order hadronic vacuum polarization contributions of those two and three pseudoscalar processes to the anomalous magnetic moment of the muon. We also estimate some higher-order additions led by the same hadronic vacuum polarization. Combined with the other contributions from the standard model, the theoretical prediction differs still by (21.6 ± 7.4) × 10−10 (2.9σ) from the experimental value.


2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ryuichiro Kitano ◽  
Hiromasa Takaura ◽  
Shoji Hashimoto

Abstract We perform a numerical computation of the anomalous magnetic moment (g − 2) of the electron in QED by using the stochastic perturbation theory. Formulating QED on the lattice, we develop a method to calculate the coefficients of the perturbative series of g − 2 without the use of the Feynman diagrams. We demonstrate the feasibility of the method by performing a computation up to the α3 order and compare with the known results. This program provides us with a totally independent check of the results obtained by the Feynman diagrams and will be useful for the estimations of not-yet-calculated higher order values. This work provides an example of the application of the numerical stochastic perturbation theory to physical quantities, for which the external states have to be taken on-shell.


2021 ◽  
Vol 103 (1) ◽  
Author(s):  
Debajyoti Choudhury ◽  
Suvam Maharana ◽  
Vandana Sahdev ◽  
Divya Sachdeva

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