Particle production in the Color Glass Condensate: from electron–proton DIS to proton–nucleus collisions

We study single inclusive hadron production in proton–proton and proton–nucleus collisions in the CGC framework. The parameters in the calculation are obtained by fitting electron–proton deep inelastic scattering data. The obtained dipole–proton amplitude is generalized to dipole–nucleus scattering without any additional nuclear parameters other than the Woods–Saxon distribution. We show that it is possible to use an initial condition without an anomalous dimension and still obtain a good description of the HERA inclusive cross section and LHC single particle production measurements. We argue that one must consistently use the proton transverse area as measured by a high virtuality probe in DIS also for the single inclusive cross section in proton–proton and proton–nucleus collisions, and obtain a nuclear modification factor RpARpA that at midrapidity approaches unity at large momenta and at all energies.