Nonperturbative-transverse-momentum broadening in dihadron angular correlations in GeV proton-nucleus collisions

GeVでの陽子-原子核衝突における2粒子角度相関の非摂動的な横運動量広がり

Aidala, C.*; 長谷川 勝一   ; 今井 憲一; 佐甲 博之   ; 佐藤 進  ; 谷田 聖   ; PHENIX Collaboration*; 他293名*

Aidala, C.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 293 of others*

The PHENIX collaboration has measured high- dihadron correlations in , Al, and Au collisions at GeV. The correlations arise from inter- and intra-jet correlations and thus have sensitivity to nonperturbative effects in both the initial and final states. The distributions of , the transverse momentum component of the associated hadron perpendicular to the trigger hadron, are sensitive to initial and final state transverse momenta. These distributions are measured multi-differentially as a function of , the longitudinal momentum fraction of the associated hadron with respect to the trigger hadron. The near-side widths, sensitive to fragmentation transverse momentum, show no significant broadening between Au, Al, and . The away-side nonperturbative widths are found to be broadened in Au when compared to ; however, there is no significant broadening in Al compared to collisions. The data also suggest that the away-side broadening is a function of , the number of binary nucleon-nucleon collisions, in the interaction. The potential implications of these results with regard to initial and final state transverse momentum broadening and energy loss of partons in a nucleus, among other nuclear effects, are discussed.