We present the first fully consistent calculation of inclusive π0
production at forward rapidities at next-to-leading order (NLO) accuracy in
proton-lead collisions at s=8.16 TeV within the Color Glass Condensate
(CGC) approach. The center-of-mass energy dependence is determined by the
Balitsky-Kovchegov (BK) equation with the initial condition constrained at NLO
accuracy by the proton structure function measurements. We find that the LHCb
data further constrain this non-perturbative input, and that both the NLO
corrections to the evolution equation and to the impact factor have significant
effects on the nuclear modification factor RpPb. The complete NLO
calculation is shown to be in qualitative agreement with the LHCb data, and the
predictions are found to be sensitive to the details of the applied DIS fit.
These results demonstrate the need to perform global analyses of DIS and LHC
data in order to probe gluon saturation phenomena at precision level at very
small momentum fraction x.Comment: 15 pages, 8 figure