Relativistic moduli space for kink collisions

The moduli space approximation to kink dynamics permits a relativistic generalization if the Derrick scaling parameter is used as collective coordinate. We develop perturbative approach resulting by expanding about unity and treating higher-order modes new degrees of freedom. This allows us resolve (coordinate) singularities order-by-order, systematically incorporates corrections {\it perturbatively} in scattering. It gives an excellent description kink-antikink collisions $\phi^4$ field theory already at first order, higher reproduces fractal structure formation final state with error only $4\%$.