Mass scale of vectorlike matter and superpartners from IR fixed point predictions of gauge and top Yukawa couplings

Abstract

We use the IR fixed point predictions for gauge couplings and the top Yukawa coupling in the MSSM extended with vectorlike families to infer the scale of vectorlike matter and superpartners. We quote results for several extensions of the MSSM and present results in detail for the MSSM extended with one complete vectorlike family. We find that for a unified gauge coupling ${\alpha }_G>0.3$ vectorlike matter or superpartners are expected within 1.7 TeV (2.5 TeV) based on all three gauge couplings being simultaneously within 1.5\% (5\%) from observed values. This range extends to about 4 TeV for ${\alpha }_G>0.2$. We also find that in the scenario with two additional large Yukawa couplings of vectorlike quarks the IR fixed point value of the top Yukawa coupling independently points to a multi-TeV range for vectorlike matter and superpartners. Assuming a universal value for all large Yukawa couplings at the GUT scale, the measured top quark mass can be obtained from the IR fixed point for $\tan \beta \simeq 4$. The range expands to any $\tan \beta >3$ for significant departures from the universality assumption. Considering that the Higgs boson mass also points to a multi-TeV range for superpartners in the MSSM, adding a complete vectorlike family at the same scale provides a compelling scenario where the values of gauge couplings and the top quark mass are understood as a consequence of the particle content of the model.

31 pages, 9 figures, typos corrected, matches the published version. v4: Appendix corrected

References in corpus (4)

• Higgs Boson Mass, Sparticle Spectrum and Little Hierarchy Problem in Extended MSSM
• Limits on Vectorlike Leptons from Searches for Anomalous Production of Multi-Lepton Events
• Unification of Gauge Couplings in the Standard Model with Extra Vector-like Families
• Universal Landau Pole and Physics below the 100 TeV Scale

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• Current status on pair-produced muon-philic vectorlike leptons in multilepton channels at the LHC
• Cascade decays of Heavy Higgs bosons through vectorlike quarks
• Leptonic cascade decays of a heavy Higgs boson through vectorlike leptons at the LHC
• Seven largest couplings of the standard model as IR fixed points
• The Two Scales of New Physics in Higgs Couplings
• SUSY scenarios according to EWSB
• Charged and neutral Higgs bosons in final states with six bottom quarks