| Issue |
EPJ Web Conf.
Volume 218, 2019
The 11th International Workshop on e+e− Collisions from Phi to Psi (PhiPsi 2017)
|
|
|---|---|---|
| Article Number | 02012 | |
| Number of page(s) | 6 | |
| Section | Hadronic Cross Section Measurements in e+e− Annihilations | |
| DOI | https://doi.org/10.1051/epjconf/201921802012 | |
| Published online | 18 October 2019 | |
https://doi.org/10.1051/epjconf/201921802012
Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector
Sezione INFN/ Pisa, Italy
* e-mail: graziano.venanzoni@pi.infn.it
Published online: 18 October 2019
I will report on the recent measurement of the fine structure constant below 1 GeV with the KLOE detector. It represents the first measurement of the running of α(s) in this energy region. Our results show a more than 5σ significance of the hadronic contribution to the running of α(s), which is the strongest direct evidence both in time-and space-like regions achieved in a single measurement. From a fit of the real part of Δα(s) and assuming the lepton universality the branching ratio BR(ω → µ+µ−) = (6.6 ± 1.4stat ± 1.7syst) · 10−5 has been determined
© The Authors, published by EDP Sciences, 2019
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