Top Quark Bound States in Finite and Holomorphic Quantum Field Theories

We propose a unified theoretical study of the recently observed threshold enhancement in top--antitop production at the LHC. First, we extend the finite, nonlocal quantum field theories to derive a modified Bethe--Salpeter equation for heavy quark--antiquark bound states, incorporating exponential regulator functions that render all loop amplitudes UV finite. We show that nonlocal propagators induce characteristic shifts in the resonance mass and width, which can be contrasted directly with LHC data. By fixing the nonlocal regulator scale in the strong sector, our framework yields a prediction of an ≈ 8.3\,pb enhancement, in excellent agreement with the CMS measurement of 8.8 ± 1.3\,pb. We analyze the renormalization group flow of the strong coupling near the top--pair threshold, introducing a holomorphic deformation inspired by unified field--theoretic constructions. We find that the modified $β$-function softens the running of αₛ, giving an enhancement of the threshold cross-section. Third, we present a systematic comparison of charmonium, bottomonium, and toponium, quantifying differences in binding energies, lifetimes, and production signatures. In particular, the top quark's large width precludes long-lived bound states, so that toponium appears only as a transient threshold resonance. Taken together, our results demonstrate that toponium not only probes nonlocal UV completions of QCD but also offers a novel window onto holomorphic renormalization group dynamics and the broader phenomenology of heavy quarkonium.