Running electroweak couplings as a probe of new physics

Daniele S.M. Alves, Jamison Galloway, Joshua T. Ruderman, Jonathan R. Walsh

    Research output: Contribution to journalArticlepeer-review


    Abstract: The energy dependence of the electroweak gauge couplings has not been measured above the weak scale. We propose that percent-level measurements of the energy dependence of α1,2 can be performed now at the LHC and at future higher energy hadron colliders. These measurements can be used to set limits on new particles with electroweak quantum numbers without relying on any assumptions about their decay properties. The shape of the high invariant mass spectrum of Drell-Yan, pp → Z** → ℓ+, constrains α1,2(Q), and the shape of the high transverse mass distribution of pp → W* → ℓν constrains α2(Q). We use existing data to perform the first fits to α1,2 above the weak scale. Percent-level measurements are possible because of high precision in theoretical predictions and existing experimental measurements. We show that the LHC already has the reach to improve upon electroweak precision tests for new particles that dominantly couple through their electroweak charges. The 14 TeV LHC is sensitive to the predicted Standard Model (SM) running of α2, and can show that α2 decreases with energy at 2-3σ significance. A future 100 TeV proton-proton collider will have significant reach to measure running weak couplings, with sensitivity to the SM running of α2 at 4-5σ and sensitivity to winos with masses up to ∼ 1.3 TeV at 2σ.

    Original languageEnglish (US)
    Article number7
    JournalJournal of High Energy Physics
    Issue number2
    StatePublished - Feb 2015


    • Beyond Standard Model
    • Renormalization Group

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics


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