  We investigate semi-inclusive photon-hadron production in the color glass
condensate (CGC) framework at RHIC and the LHC energies in proton-proton (pp)
and proton-nucleus (pA) collisions. We calculate the coincidence probability
for azimuthal correlation of pairs of photon-hadron and show that the away-side
correlations have a double-peak or a single-peak structure depending on trigger
particle selection and kinematics. This novel feature is unique for
semi-inclusive photon-hadron production compared to a similar measurement for
double inclusive dihadron production in pA collisions. We obtain necessary
conditions between kinematics variables for the appearance of a double-peak or
a single peak structure for the away-side photon-hadron correlations in pp and
pA collisions at forward rapidities and show that this feature is mainly
controlled by the ratio p_T^hadron/p_T^photon. Decorrelation of away-side
photon-hadron production by increasing the energy, rapidity and density, and
appearance of double-peak structure can be understood by QCD saturation
physics. We also provide predictions for the ratio of single inclusive prompt
photon to hadron production, and two-dimensional nuclear modification factor
for the semi-inclusive photon-hadron pair production at RHIC and the LHC at
forward rapidities.

High Energy Physics - Phenomenology;High Energy Physics - Experiment;Nuclear Theory