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Hint for axial-vector contact interactions in the data on $e^{+}e^{-} \to e^{+}e^{-}(\gamma)$ at centre-of-mass energies 192-208 GeV
For the first time the experiments ALEPH, DELPHI, L3 and OPAL have presented preliminary results for fermion-pair production in e+e- collisions on the full data set above the Z pole. A combined analysis of the Bhabha scattering measurements is performed to search for effects of contact interactions....
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Lenguaje: | eng |
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2001
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Acceso en línea: | https://dx.doi.org/10.1103/PhysRevD.64.071701 http://cds.cern.ch/record/496451 |
Sumario: | For the first time the experiments ALEPH, DELPHI, L3 and OPAL have presented preliminary results for fermion-pair production in e+e- collisions on the full data set above the Z pole. A combined analysis of the Bhabha scattering measurements is performed to search for effects of contact interactions. In the case of two axial-vector (AA) currents the best fit to the data is 2.6 standard deviations away from the Standard Model expectation, corresponding to an energy scale $\Lambda = 10.3^{+2.8}_{-1.6}$ TeV for contact interactions. For other models no statistically significant deviations are observed, and the data are used to set lower limits at 95 % confidence level on the contact interaction scales ranging from 8.2 to 21.3 TeV, depending on the helicity structure. |
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