Momentum Kick Model Analysis of PHENIX Near-Side Ridge Data and Photon Jet

Understand

We analyze PHENIX near-side ridge data for central Au+Au collisions at \sqrt{s_{NN}}=200 GeV with the momentum kick model, in which a near-side jet emerges near the surface, kicks medium partons, loses energy, and fragments into the trigger particle and fragmentation products.

• The kicked medium partons subsequently materialize as the observed ridge particles, which carry direct information on the early parton momentum distribution and the magnitude of the momentum kick.
• We find that the PHENIX ridge data can be described well by the momentum kick model and the extracted early partons momentum distribution has a thermal-like transverse distribution and a rapidity plateau structure.
• We also find that the parton-parton scattering between the jet parton and the medium parton involves the exchange of a non-perturbative pomeron, for jet partons in momentum range considered in the near-side ridge measurements.