Speaker
Description
We study the low-energy behavior of gauge couplings in the presence of dynamical scalar backgrounds. In weakly coupled, renormalizable four-dimensional theories, gauge invariance prevents tree-level modifications of the gauge kinetic term, so the dependence on scalar background is logarithmic, reflecting renormalization group structure. Large variations thus require large field excursions or many generations of charged states. Beyond one loop, other couplings, such as Yukawa or scalar couplings, which may couple directly to charged matter, can enter the gauge beta function, providing a mechanism for large variations. Extra-dimensional scenarios can evade the logarithmic limitation entirely, yielding power-law dependence while maintaining perturbative control. We discuss phenomenological implications for dynamical Standard Model gauge couplings.