Signals of unconventional E[sub 6] models at [ital e][sup +][ital e][sup [minus]] colliders

Journal Article · Sun May 01 04:00:00 EDT 1994 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.49.4394· OSTI ID:5010656

Nardi, E ^[1]

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1. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 (United States)

Generation-dependent discrete symmetries often appear in models derived from superstring theories. In particular, in the framework of E[sub 6] models the presence of such symmetries is required in order to allow for the radiative generation of naturally small neutrino masses. Recently it was shown that by imposing suitable generation-dependent discrete symmetries, a class of models can be consistently constructed in which the three sets of known fermions in each generation do not have the same assignments with respect to the 27 representation of E[sub 6]. In this scenario, the different embedding in the gauge group of the three generations implies in particular that the known charged leptons couple in a nonuniversal way to the new neutral gauge bosons ([ital Z][sub [beta]]) present in these models. We exploit this fact to study the signature of this class of models at present and future [ital e][sup +][ital e][sup [minus]] colliders. We show that some signals of deviation from lepton universality as well as some other discrepancies with the standard model predictions which have been observed at the KEK TRISTAN collider in the production rate of [mu] and [tau], can be accounted for if the [ital Z][sub [beta]] mass is not much heavier than 300 GeV. We also study the discovery limits for lepton universality violation of this type at CERN LEP 2 and at the 500 GeV [ital e][sup +][ital e][sup [minus]] Next Linear Collider (NLC). We show that models predicting unconventional assignments for the leptons will give an unmistakable signature, when the [ital Z][sub [beta]] mass is as heavy as [similar to]800 GeV (LEP 2) and [similar to]2 TeV (NLC).

• OSTI ID: 5010656
• Journal Information: Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 49:9; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BOSONS
CHARGED PARTICLES
COMPOSITE MODELS
ELECTRON-POSITRON INTERACTIONS
ELEMENTARY PARTICLES
EXTENDED PARTICLE MODEL
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NEUTRINOS
PARTICLE INTERACTIONS
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QUARK MODEL
STRING MODELS
SUPERSTRING MODELS
Z NEUTRAL BOSONS