High Hadron Correlation and No Correlation

Abstract

An overview of the correlation among high-p T hadrons produced in heavy-ion collisions is presented. Emphasis is placed on the physical processes that can quantitatively account for the data on correlations in p T , η and φ on the near and far sides. Predictions are made on processes that have no observable correlations for hadrons produced at intermediate and higher p T at RHIC and LHC.

In-medium properties of jets

“…The away-side double-hump structure is consistent not only with conical emission, but also with other physics mechanisms such as large angle gluon radiation [18] and jet 'deflection' due to radial flow or preferential selection of particles by the pathlength-dependent energy loss mechanism [19]. In order to discriminate conical emission from other mechanisms, 3-particle azimuthal correlation is needed.…”

Physics revealed at intermediatepT

“…Rapidity correlation is the oldest, dating back to the 1970s in hadronic collisions [23]. The most active area in recent years has been the use of triggers at intermediate or high p T and the observation of associated particles at various values of η and φ relative to the trigger [24][25][26]. Among the new features found, the most stimulating ones are the discovery of ridges on the near side and the double-hump structure on the away side of φ. I shall spend most of the time available to discuss the implications of the former.…”