Excited Fermion Contribution to Z Physics at One Loop

Abstract

We investigate the effects induced by excited leptons at the one-loop level in the observables measured on the $Z$ peak at LEP. Using a general effective Lagrangian approach to describe the couplings of the excited leptons, we compute their contributions to both oblique parameters and $Z$ partial widths. Our results show that the new effects are comparable to the present experimental sensitivity, but they do not lead to a significant improvement on the available constraints on the couplings and masses of these states.

25 pages 6 figures

References in corpus (4)

• Analytic approach to the complete set of QED corrections to fermion pair production in e+e- annihilation
• QED corrections with partial angular integration to fermion pair production in e+e- - annihilation
• Excited Leptonic States in Polarized e^-γand e^+ e^- Collisions
• Constraints on spin-3/2 and excited spin-1/2 fermions coming from the leptonic Z0-partial width

Cited by in corpus (6)

• Production of exotic composite quarks at the LHC
• The Two Scales of New Physics in Higgs Couplings
• Discriminating New Physics Scenarios at NLC: The Role of Polarization
• Excited lepton triplet contribution to electroweak observables at one loop level
• Limits on excited tau leptons masses from leptonic tau decays
• Excited tau lepton contribution to $W->taunu(tau)$ decay at the one-loop level