2024/01/14 by V. Bryzgalov, Bryzgalov, V. V., O. V. Zenin +1
Engineering · Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Superconducting Materials and Applications
paper · pdf · doi:10.48550/arxiv.2401.07204
openalex publication_date 2024/01/14 · openalex created_date 2024/01/18 · openalex updated_date 2026/07/28
We estimated an impact of the recent CMD-3 measurement of the e+e- → π+π- total cross section at 0.3 < √(s) < 1.2 GeV on the leading order hadronic contribution aμhad,LO to the muon anomalous magnetic moment aμ= (gμ-2)/2, in presence of comparably precise ISR measurements of the cross section by BaBar and KLOE experiments being in significant tension with the CMD-3. Assuming that all the experiments are affected by yet unidentified systematic effects, to account for the latter, we scaled the experimental uncertainties following the PDG prescription, thus facilitating a consistent joint fit of the world data on the e+e- → π+π- total cross section. The same procedure was applied in all e+e- → hadrons channels contributing to the dispersive estimate of aμhad,LO. Despite an inclusion of the new CMD-3 π+π- data, our estimate aμhad,LO(e+e-) = (696.2 ± 2.9) × 10-10 is consistent with aμhad,LO(e+e-) values obtained by other authors before publication of the CMD-3 result. Including our aμhad,LO value into the SM prediction for aμ, we obtain aμSM = (11~659~184 ± 4tot) × 10-10 which is by 4.7σ smaller than the world average for the experimental value aμexp = (11~659~205.9 ± 2.2) × 10-10. We confirm the observation by the CMD-3 authors that their σ(e+e- → π+π-) measurement, when taken alone, implies the aμSM prediction consistent with the aμexp at ∼ 1σ level.