scholarly journals Axial vector transition form factors in holographic QCD and their contribution to the anomalous magnetic moment of the muon

2020 ◽  
Vol 101 (11) ◽  
Author(s):  
Josef Leutgeb ◽  
Anton Rebhan
2019 ◽  
Vol 218 ◽  
pp. 03001
Author(s):  
Bastian Kubis

We discuss status and prospects of a dispersive analysis of the π0, η, and η ′ transition form factors. Particular focus is put on the various pieces of experimental information that serve as input to such a calculation. These can help improve on the precision of an evaluation of the light pseudoscalar pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.**


2020 ◽  
Vol 234 ◽  
pp. 01008
Author(s):  
Andrzej Kupsc

I summarize recent experimental results for two photon production of mesons. These processes include the neutral pion, η and η′ transition form factors and two photon production of pseudoscalar meson pairs. In addition I discuss the related hadronic and radiative processes. All these processes are attracting attention of experiment and theory due their relevance for the hadronic light-by-light contribution to the muon anomalous magnetic moment.


2019 ◽  
Vol 199 ◽  
pp. 02014
Author(s):  
Pablo Sanchez-Puertas ◽  
K. Kampf ◽  
J. Novotný

The radiative corrections to double-Dalitz $({P\rightarrow\overline ll\overline l'l'})$ decays are revisited and completed up to next-to-leading order in QED, finding mild differences with respect to previous studies. These might be relevant for extracting information about the mesons transition form factors, which play an important role in determining the hadronic light-by-light contribution to the anomalous magnetic moment of the muon.


2018 ◽  
Vol 166 ◽  
pp. 00012 ◽  
Author(s):  
Bastian Kubis

We discuss status and prospects of a dispersive analysis of the η and η′ transition form factors. Particular focus is put on the various pieces of experimental information that serve as input to such a calculation. These can help improve on the precision of an evaluation of the η and η′ pole contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.


2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Josef Leutgeb ◽  
Jonas Mager ◽  
Anton Rebhan

AbstractWe review the recent progress made in using holographic QCD to study hadronic contributions to the anomalous magnetic moment of the muon, in particular the hadronic light-by-light scattering contribution, where the short-distance constraints associated with the axial anomaly are notoriously difficult to satisfy in hadronic models. This requires the summation of an infinite tower of axial vector mesons, which is naturally present in holographic QCD models, and indeed takes care of the longitudinal short-distance constraint due to Melnikov and Vainshtein. Numerically the results of simple hard-wall holographic QCD models point to larger contributions from axial vector mesons than assumed previously, while the predicted contributions from pseudo-Goldstone bosons agree nicely with data-driven approaches.


2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Ken Sasaki

Abstract The contribution to the muon anomalous magnetic moment from the fermion triangle loop diagrams connected to the muon line by a photon and a $Z$ boson is re-analyzed in both the unitary gauge and the ’t Hooft–Feynman gauge. With use of the anomalous axial-vector Ward identity, it is shown that the calculation in the unitary gauge exactly coincides with the one in the ’t Hooft–Feynman gauge. The part which arises from the ordinary axial-vector Ward identity corresponds to the contribution of the neutral Goldstone boson. For the top-quark contribution, the one-parameter integral form is obtained up to the order of $m_\mu^2/m_Z^2$. The results are compared with those obtained by the asymptotic expansion method.


Sign in / Sign up

Export Citation Format

Share Document