Return of the technicolour

Abstract

We discuss that conventional Technicolour dynamics can be revitalized within the Dark Technicolour paradigm by invoking the Extended Most Attractive Channel hypothesis. In this framework, Standard Model fermions acquire masses via multifermion chiral condensates arising from new strong dynamics. The model incorporates three confining gauge sectors, Technicolour, Dark Technicolour, and an intermediate QCD-like sector, linked through extended gauge symmetries. The Extended Most Attractive Channel hypothesis reveals a hierarchical structure of condensates, where channels with higher net chirality become increasingly attractive. At low energies, the Dark Technicolour paradigm naturally reduces to the Froggatt-Nielsen or Standard Hierarchical Vacuum Expectation Value model, governed by residual discrete symmetries, offering a compelling resolution to the Standard Model Flavor Problem.

Figures (6)

• Figure 1: The matter problem
• Figure 2: The flavour problem
• Figure 3: At low energies, the DTC paradigm may effectively reduce to either the SHVM or the Froggatt–Nielsen mechanism, depending on the prevailing symmetry-breaking pattern.
• Figure 4: The Feynman diagrams for the masses of charged fermions in the DTC paradigm. The top part shows the generic interactions of the SM, TC, DQCD and DTC fermions. In the lower part of figure, the formations of the TC chiral condensates, $\langle \varphi \rangle$ (circular blob), a generic multifermion chiral condensates $\langle \chi_r \rangle$ (collection of circular blobs), and the resulting mass of the SM charged fermion is depicted.
• Figure 5: Feynman diagrams for neutrino mass generation in the DTC paradigm. The top panel shows interactions among SM, TC, DQCD, and DTC sectors via ETC, EDTC, and GUT bosons. The bottom panel illustrates the effective diagram after condensate formation.