  We show that in proton-lead (p+Pb) collisions at the LHC, the Color Glass
Condensate (CGC) and hydrodynamics lead to qualitatively different behavior of
the average transverse momentum, <p_T>, with the particles rapidity. In
hydrodynamics, the <p_T> decreases as one goes from zero rapidity, y=0, to the
proton fragmentation region since the number of particles decreases. In
contrast, in the CGC the saturation momentum increases as one goes from y=0 to
the proton fragmentation region, and so the <p_T> increases. At the LHC, the
difference between the two models may be large enough to be tested
experimentally.
