Measurement of the Running of the Electromagnetic Coupling at LEP
نویسنده
چکیده
The study of low-angle and large-angle Bhabha scattering at LEP gives access to the running of the electromagnetic coupling. Two recent measurements of the OPAL and L3 collaborations probe the running of α in the regions 1.8 GeV < −Q < 6.1 GeV and 1800 GeV < −Q < 21600 GeV, respectively. The strategies and the results of these studies are presented. A global overview is given of the agreement of these and previous L3 findings with the QED predictions. To appear in the Proceedings of the International Europhysics Conference on High Energy Physics July 21st 27th 2005, Lisboa, Portugal
منابع مشابه
Measurements of the Running of the Electromagnetic Coupling at LEP
The study of Bhabha scattering at ee colliders probes the running of the electromagnetic coupling. After early measurements by the VENUS collaboration at TRISTAN and the by L3 collaboration at LEP, two recent analyses have been performed by the OPAL and L3 collaborations. The OPAL collaboration studied highstatistics low-angle Bhabha scattering at LEP, achieving a precise determination of the r...
متن کاملA Non-Demolition Photon Counting Method by Four-Level Inverted Y-Type Atom
The semi-classical model of atom-field interaction has been fully studied for some multilevel atoms, e.g. Vee, L, Cascade X , Y, and inverted Y and so on. This issue is developed into the full-quantum electrodynamics formalism, where the probe and coupling electromagnetic fields are quantized. In this article, we investigate the full-quantum model of absorption and dispersion spectrum of trappe...
متن کاملRunning of the Qed Coupling in Small-angle Bhabha Scattering at Lep
Using the OPAL detector at LEP, the running of the effective QED coupling α(t) is measured for space-like momentum transfer, 2 ≤ −t ≤ 6 GeV, from the angular distribution of smallangle Bhabha scattering. This is currently the most significant direct observation of the running of the QED coupling in a single experiment and the first clear evidence of the hadronic contribution to the running in t...
متن کاملDifermion Cross-sections at Lepii
Precision measurements at LEPII provide a unique test of Standard Model predictions. Results from the four LEP collaborations ALEPH, DELPHI, L3 and OPAL on the difermion cross-sections and asymmetries obtained at centre-of-mass energies between 192 and 202 GeV are presented. The high s ′ results are used to determine the running of the electromagnetic coupling constant and the strength of the i...
متن کاملExposure to electromagnetic fields at two call centers in Turkey, 2015
Background: This study aims to evaluate the negative health impacts of exposure to electromagnetic field and to prepare a risk map of two selected call centers. Materials and Methods: Two call centers whose electromagnetic field values were measured by calibrated low high and point frequency measurement device. The measurements were performed by following the EN 50492 Standards. 178 employees ...
متن کامل