The Momentum Kick Model Description of the Near-Side Ridge and Jet Quenching

TL;DR

The paper presents the momentum kick model explaining the near-side ridge and jet quenching phenomena in heavy-ion collisions, linking observed particle distributions to jet-medium interactions and initial parton conditions.

Contribution

It introduces a detailed description of the momentum kick model, extracting initial parton distributions and explaining ridge formation and jet quenching in heavy-ion collisions.

Findings

Initial parton distribution is thermal-like with a rapidity plateau.

Ridge particles reflect the momentum transfer from jets to medium.

Model explains centrality dependence of ridge yield and jet quenching.

Abstract

In the momentum kick model, 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 magnitude of the momentum kick and the initial parton momentum distribution at the moment of jet-(medium parton) collisions. The initial parton momentum distribution extracted from the STAR ridge data for central AuAu collisions at \sqrt{s_{NN}}=200 GeV has a thermal-like transverse momentum distribution and a rapidity plateau structure with a relatively flat distribution at mid-rapidity and sharp kinematic boundaries at large rapidities. Such a rapidity plateau structure may arise from particle production in flux tubes, as color charges and anti-color charges separate at high energies. The centrality dependence of the ridge yield and the degree of jet quenching can be consistently described by the momentum kick model.