English

QCD parameters and SM-high precisions from $e^+e^-\to$ Hadrons : Summary

High Energy Physics - Phenomenology 2024-02-26 v2 High Energy Physics - Experiment High Energy Physics - Lattice

Abstract

In this talk, I summarize the results obtained recently in Ref.\,\cite{SNe} using the PDG 22 compilation of the e+ee^+e^-\to Hadrons \oplus the recent CMD3 data for the pion form factor. Using the gluon condensate αsG2=(6.49±0.35)×102\langle \alpha_s G^2\rangle=(6.49\pm 0.35)\times 10^{-2} GeV4^4 from heavy quark sum rules, the extracted QCD four-quark and dimension eight condensate condensates values are: ραsψˉψ2=(5.98±0.64)×104\rho\alpha_s\langle\bar\psi\psi\rangle^2= (5.98\pm 0.64)\times 10^{-4} GeV6^6 and d8=(4.3±3.0)×102d_8= (4.3\pm 3.0)\times 10^{-2} GeV8^8 from the ratio R10{\cal R}_{10} of Laplace sum rules to order αs4\alpha_s^4. Inversely using these estimated values of the condensates, we obtain from R10{\cal R}_{10}: αsG2=(6.12±0.61)×102\langle \alpha_s G^2\rangle=(6.12\pm 0.61)\times 10^{-2} GeV4^4 which leads to the average (6.40±0.30)×102(6.40\pm 0.30)\times 10^{-2} GeV4^4. %from light and heavy quark systems. Using the lowest τ\tau-like decay moment, the mean result of Fixed Order (FO) and Contour Improved (CI) PT series within the standard OPE is : αs(Mτ)=0.3385(50)(136)syst\alpha_s(M_\tau)=0.3385(50)(136)_{syst} [resp. 0.3262(37)(78)syst0.3262(37)(78)_{syst}] to order αs4\alpha_s^4 [resp. αs5\alpha_s^5] leading to αs(MZ)\alpha_s(M_Z)=0.1207(17)(3) [resp. 0.1193(11)(3)], while the sum of the non-perturbative contribution at MτM_\tau is\,: δNPV(Mτ)=(2.3±0.2)×102\delta^V_{NP}(M_\tau)=(2.3\pm 0.2)\times 10^{-2}. Using the same data, one also obtains the LO hadronic vacuum polarization to the muon and τ\tau anomalous magnetic moments: aμl.ohvp=(7036.5±38.9)×1011,aτl.ohvp=(3494.8±24.7)×109a_\mu\vert^{hvp}_{l.o}= (7036.5\pm 38.9)\times10^{-11}, \, a_\tau\vert^{hvp}_{l.o}= (3494.8\pm 24.7)\times10^{-9} which leads to : Δaμaμexpaμth=(143±42th±22exp)×1011\Delta a_\mu\equiv a_\mu^{exp}-a_\mu^{th} = (143\pm 42_{th}\pm 22_{exp})\times 10^{-11} indicating about 3σ\sigma discrepancy between the SM predictions and experiment. One also finds: α(5)(MZ)had=(2766.3±4.5)×105\alpha^{(5)}(M_Z)\vert_{had}=(2766.3\pm 4.5)\times 10^{-5}.

Keywords

Cite

@article{arxiv.2309.05342,
  title  = {QCD parameters and SM-high precisions from $e^+e^-\to$ Hadrons : Summary},
  author = {Stephan Narison},
  journal= {arXiv preprint arXiv:2309.05342},
  year   = {2024}
}

Comments

11 pages, 17 figures, 3 Tables, Talk given at the 26th international conference in HEP (QCD23), 10-14th july 2023, Montpellier-FR. The comparison of the muon anomaly with the new experiment is updated. Some misprints have been corrected. Version to appear in Nuclear and Particle Physics Proceedings

R2 v1 2026-06-28T12:17:50.716Z