Ultra-relativistic oscillon collisions
  In this short note we investigate the ultra-relativistic collisions of small amplitude oscillons in 1+1 dimensions. Using the amplitude of the oscillons and the inverse relativistic boost factor $\gamma^{-1}$ as the perturbation variables, we analytically calculate the leading order spatial and temporal phase shifts, and the change in the amplitude of the oscillons after the collisions. At leading order, we find that only the temporal phase shift receives a nonzero contribution, and that the collision is elastic. This work is also the first application of the general kinematic framework for understanding ultra-relativistic collisions (arXiv:1308.0606) to intrinsically time-dependent solitons. 
Mustafa A. Amin, Indranil Banik, Carina Nagreanu and I-Sheng Yang
hep-th astro-ph.HE nlin.PS