Collisional interactions between self-interacting non-relativistic boson
  stars: effective potential analysis and numerical simulations
  Scalar particles are a common prediction of many beyond the Standard Model
theories. If they are light and cold enough, there is a possibility they may
form Bose-Einstein condensates, which will then become gravitationally bound.
These boson stars are solitonic solutions to the Einstein-Klein-Gordon
equations, but may be approximated in the non-relativistic regime with a
coupled Schr\"odinger-Poisson system. General properties of single soliton
states are derived, including the possibility of quartic self-interactions.
Binary collisions between two solitons are then studied, and the effects of
different mass ratios, relative phases, self-couplings, and separation
distances are characterized, leading to an easy conceptual understanding of how
these parameters affect the collision outcome in terms of conservation of
energy. Applications to dark matter are discussed.
