Ridge Structure in the {Delta/phi-Delta/eta} Correlation Function Associated with a Near-Side Jet...

In the {Delta/phi-Delta/eta} correlation associated with a near-side jet observed in heavy-ion collisions at RHIC [Ref. 1-4], the ridge structure can be explained by the momentum kick model in which the ridge particles are identified as medium partons which suffer collision with the jet and acquire a momentum kick along the jet direction. If this is indeed the correct mechanism, the ridge structure associatd with the near-side jet may be used to probe the momentum distribution of partons at the moment of the jet-parton collision, leading to the result that the rapidity width of partons at the moment of the jet-parton collision is greater than the rapidity width of the inclusive particles at the end point of the nucleus-nucleus collision.