Study of fermion pair production in $\mathrm{e^+ e^-}$ collisions at 130–183 GeV

Abstract.

The cross sections and forward-backward asymmetries of hadronic and leptonic events produced in ${\rm e}^+{\rm e}^-$ collisions at centre-of-mass energies from 130 to 183 GeV are presented. Results for ${\rm e}^+{\rm e}^-$, $\mu^+\mu^-$, $\tau^+\tau^-$, ${\rm q}\bar{\rm q}$, ${\rm b\bar b}$ and ${\rm c\bar c}$ production show no significant deviation from the Standard Model predictions. This enables constraints to be set upon physics beyond the Standard Model such as four-fermion contact interactions, leptoquarks, ${\rm Z}^\prime$ bosons and R-parity violating squarks and sneutrinos. Limits on the energy scale $\Lambda$ of ${\rm e}^+{\rm e}^-{\rm f\bar f}$ contact interactions are typically in the range from 2 to 10 TeV. Limits on R-parity violating sneutrinos reach masses of a few hundred GeV/$c^2$ for large values of their Yukawa couplings.