Shadowing in inelastic nucleon-nucleon cross section?

Experimental results of inclusive hard-process cross sections in heavy-ion collisions conventionally lean on a normalization computed from Glauber models where the inelastic nucleon-nucleon cross section ${\sigma }_{\mathrm{n}\mathrm{n}}^{\mathrm{i}\mathrm{n}\mathrm{e}\mathrm{l}}$ – a crucial input parameter – is simply taken from proton-proton measurements. In this letter, using the computed electro-weak boson production cross sections in lead-lead collisions as a benchmark, we determine ${\sigma }_{\mathrm{n}\mathrm{n}}^{\mathrm{i}\mathrm{n}\mathrm{e}\mathrm{l}}$ from the recent ATLAS data. We find a significantly suppressed ${\sigma }_{\mathrm{n}\mathrm{n}}^{\mathrm{i}\mathrm{n}\mathrm{e}\mathrm{l}}$ relative to what is usually assumed, show the consequences for the centrality dependence of the cross sections, and address the phenomenon in an eikonal minijet model with nuclear shadowing.