Light bound states of heavy fermions

In the Standard Model, a group of heavy fermions, e.g. top quarks, can collectively strongly affect the Higgs field and create relatively long-lived bound states. If there exist new generations of fermions with masses beyond 1 TeV, strong binding of several of them can make them lighter than even a single heavy fermion. Using the mean field approximation we find multi-fermion states with masses M ∼ 5 v N ≈ 1.2 N TeV , with N = 2 , 3 , … and v = 246 GeV being the total number of heavy fermions bound together, and the Higgs VEV. These results inspire a hope that the experimental search for multi-fermions within the range of energies 2–3 Tev would either discover them, or suggest absence of new Standard Model fermions with larger masses. Possible implications related to multi-top states and baryonic asymmetry of the Universe are discussed.