CONSTRAINTS FROM LEPTON UNIVERSALITY AT THE Z PEAK ON UNIFIED THEORIES

Abstract

We suggest the use of a universality-breaking observable based on lepton asymmetries as derived from the left-right asymmetry and the $\tau$ polarization at the $Z$ peak, which can efficiently constrain the parameter space of unified theories. The new observable is complementary to the leptonic partial width differences and it depends critically on the chirality of a possible non-universal $Z$-boson coupling to like-flavour leptons. The LEP/SLC potential of probing universality violation is discussed in representative low-energy extensions of the Standard Model (SM) that could be derived by supersymmetric grand unified theories, such as the SM with left-handed and/or right-handed neutral isosinglets, the left-right symmetric model, and the minimal supersymmetric SM.

LaTeX file, 13 pages (2 figures available upon request)

References in corpus (5)

• Limits on Neutrino Mixing with new Heavy Particles
• Precise Measurement of the Left-Right Cross Section Asymmetry in $Z$ Boson Production by $\ee$ Collisions
• Leptonic Flavor-changing Z0 Decays in SU(2)xU(1) Theories with Right- handed Neutrinos
• Universality-Breaking Effects in Leptonic Z Decays
• Reconciling the LEP and Slac Measurements of Sin^2(Θ_W)

Cited by in corpus (17)

• Resonant Leptogenesis
• CP Violation and Baryogenesis due to Heavy Majorana Neutrinos
• W- and Z-Boson Interactions in Supersymmetric Models with Explicit R-Parity Violation
• Mixing Renormalization in Majorana Neutrino Theories
• Cumulative Non-Decoupling Effects of Kaluza-Klein Neutrinos in Electroweak Processes
• SEMILEPTONIC LEPTON-NUMBER/FLAVOUR-VIOLATING tau DECAYS IN MAJORANA NEUTRINO MODELS
• Gauge and Scheme Dependence of Mixing Matrix Renormalization
• Probing Lepton-number/flavour-violation in Semileptonic Tau Decays into Two Mesons
• Lepton Flavor Violation in Z and Lepton Decays in Supersymmetric Models
• Supersymmetry without R-parity : Constraints from Leptonic Phenomenology
• Non-decoupling and lepton number violation in left-right models
• Lepton-Flavor Violating Decays of the $Z$-boson in a Left-Right Supersymmetric Model
• Gauge-Independent Analysis of K_L --> e μin Left-Right Models
• Weak Magnetic Dipole Moments in the MSSM
• CP violation through particle mixing and the H-A lineshape
• On-shell renormalization of the mixing matrices in Majorana neutrino theories
• Doubly charged Higgsino contribution to the decays mu-->e photon and mu-->3e and to the anomalous magnetic moment of the muon within the left-right supersymmetric model