2025/03/27 by Hill, Christopher T. · 1 citation
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2503.21518
The Nambu--Jona-Lasinio (NJL) model involves a pointlike 4-fermion interaction. While it gives a useful description of chiral dynamics (mainly in QCD), it nonetheless omits the crucially important internal wave-function of a two-body bound state, ϕ(r). This becomes significant near critical coupling where ϕ(r) extends to large distance, leading to dilution and suppression of induced couplings ∝ ϕ(0), such as the Yukawa and quartic couplings, as well as reduced fine-tuning of a hierarchy. In top quark condensation, where the BEH boson is a tt bound state and we have a UV completion such as topcolor, we must go beyond the NJL model and include effects of ϕ(r). We provide a formulation of this for the Brout-Englert-Higgs boson, and find that it leads to an extended ϕ(r), a significantly reduced and natural composite scale of M0 ∼ 6 TeV, a successful prediction for the quartic coupling, λ, and fine tuning that is reduced to a few percent, providing a compelling candidate solution to the naturalness problem of the BEH boson. The theory is testable and new physics should begin to emerge on the multi-TeV mass scales and possibly accessible to the LHC.