Eur. Phys. J. C 6, 1-18
Tests of the Standard Model and constraints
on new physics from measurements of fermion-pair production
at 183GeV at LEP
The OPAL Collaboration
G.Abbiendi2 et al.
2 Dipartimento di Fisica dell' Università di Bologna and INFN, I-40126 Bologna, Italy
Received: 3 July 1998 / Published online: 15 October 1998
Cross-sections for hadronic, and lepton pair final states in collisions at =183GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. Forward-backward asymmetries for the leptonic final states have also been measured. Cross-sections and asymmetries are also presented for data recorded in 1997 at =130 and 136GeV. The results are used to measure the energy dependence of the electromagnetic coupling constant , 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 leptoquark, or of a squark or sneutrino in supersymmetric theories with R-parity violation.