Measurement of emission-angle anisotropy via long-range angular correlations with high- pT hadrons in d+Au and p+p collisions at s NN =200 GeV

We present measurements of two-particle angular correlations between high-transverse-momentum (2<pT<11 GeV/c) π0 observed at midrapidity (|η|<0.35) and particles produced either at forward (3.1<η<3.9) or backward (−3.7<η<−3.1) rapidity in d+Au and p+p collisions at √sNN=200 GeV. The azimuthal angle correlations for particle pairs with this large rapidity gap in the Au-going direction exhibit a characteristic structure that persists up to pT≈6 GeV/c and which strongly depends on collision centrality, which is a similar characteristic to the hydrodynamical particle flow in A+A collisions. The structure is absent in the d-going direction as well as in p+p collisions, in the transverse-momentum range studied. The results indicate that the structure is shifted in the Au-going direction toward more central collisions, similar to the charged-particle pseudorapidity distributions.