The Ridge Associated with the Near-side Jet in High Energy-Heavy-Ion Collisions

Abstract

The ridge particles associated with a near-side jet are identified as medium partons kicked by the jet near the surface. They carry direct information on the parton momentum distribution at the moment of jet-parton collisions and the magnitude of the longitudinal momentum kick. The extracted early parton momentum distribution has a rapidity plateau structure with a thermal-like transverse momentum distribution. Such a rapidity plateau structure may arise from particle production in flux tubes, as color charges and anti-color charges separate at high energies.