“…Similar ∆φ-∆η correlations associated with a near-side jet have also been observed by the PHENIX Collaboration [16,17] and the PHOBOS Collaboration [18]. While many theoretical models [19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35] have been proposed to discuss the jet structure and related phenomena, the ridge phenomenon has not yet been fully understood.…”