  We combine the first-quantized path-integral formalism and bosonization to
develop a phenomenological theory for spin-charge coupled dynamics in
one-dimensional (1D) ferromagnetic systems with strong interparticle repulsion,
at low temperatures. We assume an effective spin-charge separation and retain
the standard Luttinger-liquid plasmon branch, which is explicitly coupled to a
ferromagnetic spin-wave texture with a quadratic dispersion. The dynamic spin
structure severely suppresses the plasmon peak in the single-particle
propagator, in both fermionic and bosonic systems. Our analysis provides an
effective theory for the new universality class of 1D ferromagnetic systems,
capturing both the trapped spin and propagating spin-wave regimes of the
long-time behavior.
