Hadronic light-by-light contribution to the muon g — 2

30th Annual Meeting of the Division of Particles and Fields (DPyC) of the Mexican Physical Society

Guevara, Adolfo^1

Departamento de Fisica, Cinvestav Del IPN, Apdo. Postal 14-740, Mexico DF.

07000, Mexico^1

关键词: Accurate prediction;    Anomalous magnetic moments;    Chiral perturbation theory;    Dynamical fields;    Invariant-mass spectra;    Light contribution;    Pole approximation;    Resonance multiplets;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/761/1/012009/pdf
DOI  :  10.1088/1742-6596/761/1/012009

来源: IOP

【 摘 要 】

We have computed the hadronic light-by-light (LbL) contribution to the muon anomalous magnetic moment aμin the frame of Chiral Perturbation Theory with the inclusion of the lightest resonance multiplets as dynamical fields (RχT). It is essential to give a more accurate prediction of this hadronic contribution due to the future projects of J-Parc and FNAL on reducing the uncertainty in this observable. We, therefore, computed the pseudoscalar transition form factor and proposed the measurement of the e+ e-→μ+μ-π0cross section and dimuon invariant mass spectrum to determine more accurately its parameters. Then, we evaluated the pion exchange contribution to αμ, obtaining (6.66 ± 0.21) • 10-10. By comparing the pion exchange contribution and the pion-pole approximation to the corresponding transition form factor (πTFF) we recalled that the latter underestimates the complete πTFF by (15-20)%. Then, we obtained the η(')TFF, obtaining a total contribution of the lightest pseudoscalar exchanges of (10.47 ± 0.54) • 10-10, in agreement with previous results and with smaller error.