Conveners
R-ratio
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R-ratio
- Fedor Ignatov (University of Liverpool)
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Tatyana Kharlamova (BINP)08/06/2026, 12:35
This report presents precision measurements of the total cross section for $e^+e^-$ annihilation into hadrons, performed with the KEDR detector at the VEPP-4M collider. The KEDR collaboration has measured the $R$ values at 22 center-of-mass energies between 1.84 and 3.72 GeV with the highest accuracy achieved to date. In addition, the energy region from 4.56 to 6.96 GeV was scanned at 17...
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Weiping Wang08/06/2026, 17:20
The inclusive measurement of R, which is the ratio of the leading-order cross sections between inclusive hadronic events and a pair of muon leptons, is of great importance in the precision test of the Standard Model. For example, the determination of QED running coupling constant at the Z pole, the evaluation of the muon anomaly, and search and study of exotic hadron states. We will introduce...
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Diogo Boito (University of Sao Paulo)08/06/2026, 17:45
We assess the theory prediction for $R(s)$ below the charm threshold and address tensions with the existing data, notably with the 2021 BES-III results. We provide an analysis of the theory uncertainty associated with perturbative QCD in the light of renormalon calculus, and show that the perturbative series is well behaved and under good control. We provide a reliable and conservative...
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