Crawling technicolor.

We analyze the Callan-Symanzik (CS) equations when scale invariance at a nontrivial infrared (IR) fixed point $\alpha^{}_\mathrm{IR}$ is realized in the Nambu-Goldstone (NG) mode. As a result, Green's functions at $\alpha^{}_\mathrm{IR}$ do not scale as for the conventional Wigner-Weyl (WW) mode. This allows us to propose a new mechanism for dynamical electroweak symmetry breaking where the running coupling $\alpha$ "crawls" towards (but does not pass) $\alpha^{}_\mathrm{IR}$ in the exact IR limit. The NG mechanism at $\alpha^{}_\mathrm{IR}$ implies the existence of a massless dilaton $\sigma$, which becomes massive for IR expansions in $\epsilon \equiv \alpha^{}_\mathrm{IR} - \alpha$ and is identified with the Higgs boson. Unlike "dilatons" that are close to a WW-mode fixed point or associated with a Coleman-Weinberg potential, our NG-mode dilaton is genuine and hence naturally light. Its (mass)$^2$ is proportional to $\epsilon \beta'(4+\beta')F_\sigma^{-2} \langle\hat{G}^2\rangle_{\mathrm{vac}}$, where $\beta'$ is the (positive) slope of the beta function at $\alpha^{}_\mathrm{IR}$, $F_\sigma$ is the dilaton decay constant and $\langle\hat{G}^2\rangle_{\mathrm{vac}}$ is the technigluon condensate. Using an effective field theory analysis, we find a closed form of the Higgs potential with $\beta'$-dependent deviations from that of the Standard Model (SM). Flavor-changing neutral currents (FCNCs) are suppressed if the crawling region $\alpha \lesssim \alpha^{}_\mathrm{IR}$ includes a sufficiently large range of energies above the TeV scale. In an appendix, we observe that, contrary to folklore, condensates protect fields from decoupling in the IR limit.