Eur. Phys. J. C (1998) 5: 155-165
https://doi.org/10.1007/s100529800824

Theoretical physics

Constraints on four-Fermi contact interactions from low-energy electroweak experiments

¹ Theory Group, KEK, 305, Tsukuba, Ibaraki, Japan
² ICEPP, University of Tokyo, Hongo, Bunkyo-ku, 113, Tokyo, Japan
³ Theory Division, CERN, CH-1211, Genève 23, Switzerland

Received: 28 November 1997
Published online: 16 September 2013

Abstract

We investigate the constraints on four-Fermi contact interactions from low-energy lepton-quark and lepton-lepton scattering experiments — polarization asymmetries in electron (muon)-nucleon scattering experiments, cesium and thallium atom parity violation measurements, neutrino-nuclei and neutrino-electron scattering experiments. These constraints are then combined by assuming the lepton and quark universalities and SU(2)_L x U(l)_y gauge invariance of the contact interaction, which leave independent six lepton-quark and three pure-leptonic interactions. Impacts of these constraints on models with an additional Z-boson are briefly discussed. We also present updates of the low-energy constraints on the S and T parameters.