2024/07/02 by J. McDonald, McDonald, John · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #Particle physics theoretical and experimental studies #Relativity and Gravitational Theory
paper · doi:10.48550/arxiv.2407.02399
openalex publication_date 2024/07/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Standard Model (SM) Higgs potential is likely to be metastable, in which case Higgs Inflation requires an extension of the SM to sufficiently stabilise the Higgs potential. Here we consider stabilisation by adding nQ ≤ 3 Vector-Like Quarks (VLQs) of mass mQ. We consider isosinglet T and B vector quarks. Requiring stability of the finite temperature effective potential, we find that the upper bounds on mQ for T quarks are 5.8 TeV (for nQ = 2) and 55 TeV (for nQ = 3). The upper bounds are generally smaller for B vector quarks and are sensitive to the t-quark mass. The inflation predictions depend upon the conformal frame in which the model is renormalised. For renormalisation in the Einstein frame (Prescription I) the predictions are almost indistinguishable from the classical values: ns = 0.966 and r = 3.3 × 10-3. Renormalisation in the Jordan frame (Prescription II) predicts larger values of ns and r, with ns generally in the range 0.980 to 0.990 and r of the order of 0.01. The predicted range of ns is consistent with the CMB range obtained in Hubble tension solutions which modify the sound horizon at decoupling, whilst the predicted values of r will be easily observable by forthcoming CMB experiments. The observational upper bound on r generally imposes a stronger upper bound on mQ in Prescription II than the requirement of stability. We conclude that VLQ-stabilised Higgs Inflation with Prescription II renormalisation favours 1-10 TeV vector-like quarks that will be accessible to future colliders, and predicts a tensor-to-scalar ratio that will be observable in forthcoming CMB experiments and values of ns that favour an early-time solution to the Hubble tension.