Asymptotically Safe Standard Model Extensions

Preprint number: CP3-Origins-2017-29 DNRF90
Authors: Giulio Maria Pelaggi (Pisa University), Alexis D. Plascencia (IPPP Durham), Alberto Salvio (CERN), Francesco Sannino (CP3-Origins & DIAS & CERN), Juri Smirnov (Firenze University), and Alessandro Strumia (CERN and Pisa)
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We construct asymptotically safe extensions of the Standard Model in which the weak and hypercharge gauge couplings are made safe via the addition of a large number of extra charged fermions. To achieve safety also in the Higgs self-coupling, the minimal construction features a right-handed neutrino around $10^{14}GeV$.
A natural variant, with all new masses close to the Fermi scale,
is obtained by implementing a TeV-scale double see-saw mechanism.
We also construct models featuring dynamical generation of scales that include Dark Matter candidates. The large extra degrees of freedom allow for intriguing atypical phenomenological scenarios, such as cold Dark Matter arising from a relativistic freeze-out.