Inclusive Ridge Distributions in Heavy-Ion Collisions
  The formation of ridges induced by semihard scattering in nuclear collisions is included in the description of single-particle distributions for both pion and proton at low transverse momenta. The ridge component is characterized by an azimuthal dependent factor that is derived in the study of the ridge structure in two-particle correlation distributions involving triggers. It is shown that the inclusive ridge can reproduce the observed data on $v_2(p_T)$ if the base component underlying the ridge has no azimuthal dependence. A common description of pion and proton spectra is given in the recombination model that can smoothly join the low- and intermediate-$p_T$ regions. All the important properties of single-particle distributions in those regions can be satisfactorily described in this approach. 
Rudolph C. Hwa and Lilin Zhu
nucl-th