Tests of the standard model and constraints on new physics from measurements of fermion-pair production at 189 GeV at LEP

The OPAL Collaboration:     G. Abbiendi - et al.

doi:doi:10.1007/s100520000315

EPJ

Tests of the standard model and constraints on new physics from measurements of fermion-pair production at 189GeV at LEP

The OPAL Collaboration

G.Abbiendi² - et al.

²Dipartimento di Fisica dell' Università di Bologna and INFN, I-40126 Bologna, Italy

Abstract
Cross-sections and angular distributions for hadronic and lepton pair final states in e⁺e^- collisions at a centre-of-mass energy near 189GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. The results are used to measure the energy dependence of the electromagnetic coupling constant $\alpha_{\mathrm{em}}$ , and to place limits on new physics as described by four-fermion contact interactions or by the exchange of a new heavy particle such as a sneutrino in supersymmetric theories with R-parity violation. A search for the indirect effects of the gravitational interaction in extra dimensions on the $\mu^+\mu^-$ and $\tau^+\tau^-$ final states is also presented.

23rd International Summer School on Vacuum, Electron, and Ion Technologies (VEIT)
18-22 September 2023
Sozopol, Bulgaria

EPJ

Tests of the standard model and constraints on new physics from measurements of fermion-pair production at 189GeV at LEP

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