Constraints on four-Fermi contact interactions from low-energy electroweak experiments
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
Published online: 16 September 2013
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.
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