Observation of a "Ridge" correlation structure in high multiplicity   proton-proton collisions: A brief review
  This paper briefly reviews the striking experimental observation of a ridge-like dihadron correlation structure in high multiplicity proton-proton collisions at the Large Hadron Collider (LHC). Recent progress of both experimental and theoretical efforts on understanding the physical origin of the novel effect is reviewed. Outlook on future direction of possible new studies is discussed. 
Wei Li
nucl-ex hep-ex