A shoving model for collectivity in hadronic collisions
  An extension of the rope hadronization model, which has previously provided good descriptions of hadrochemistry in high multiplicity pp collisions, is presented. The extension includes a dynamically generated transverse pressure, produced by the excess energy from overlapping strings. We find that this model can qualitatively reproduce soft features of Quark Gluon Plasma in small systems, such as higher $\langle p_\perp \rangle$ for heavier particles and long range azimuthal correlations forming a ridge. The effects are similar to those obtained from a hydrodynamic expansion, but without assuming a thermalized medium. 
Christian Bierlich, G\"osta Gustafson, Leif L\"onnblad
hep-ph nucl-th