What Precision Electroweak Physics Says About the SU(6)/Sp(6) Little Higgs
5/26/2003
133 citations (127 excluding self-citations). One of the key precision electroweak analyses of the Little Higgs program, establishing that realistic parameter space survives LEP constraints.
The Problem
Little Higgs models predict new heavy gauge bosons and fermions at the TeV scale. These particles contribute to precision electroweak observables measured at LEP and SLD, potentially conflicting with data. The SU(6)/Sp(6) model, a close cousin of the Littlest Higgs, needed a careful analysis of whether its predicted spectrum was compatible with the tight precision constraints.
The Key Results
The paper identifies a “near-oblique limit” where the heavy W’ and B’ decouple from light fermions, allowing the precision constraints to be computed using the familiar S, T, U parameters plus one-loop corrections from the extended top sector. The result: viable parameter space exists with only mild fine-tuning, with top partners as light as 1 TeV, W’ as light as 1.8 TeV, and the B’ potentially as light as a few hundred GeV. The lightest Higgs mass is relatively unconstrained by precision data, a result that distinguished this model from the Standard Model where precision constraints favor a light Higgs for different reasons.
Recollections
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