Long-range azimuthal correlations in proton-proton and proton-nucleus   collisions from the incoherent scattering of partons
  We show that the incoherent elastic scattering of partons, as present in a multi-phase transport model (AMPT), with a modest parton-parton cross-section of $\sigma=1.5 - 3$ mb, naturally explains the long-range two-particle azimuthal correlation as observed in proton-proton and proton-nucleus collisions at the Large Hadron Collider. 
Guo-Liang Ma and Adam Bzdak
hep-ph nucl-ex nucl-th