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