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arXiv · 2504.07514

Probing fluctuating protons using forward neutrons in soft and hard inelastic proton-nucleus scattering

M. Alvioli·V. Guzey·M. Strikman
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Abstract

We present a model for the distribution of the number of forward neutrons emitted in soft (minimum bias) and hard inelastic proton-nucleus ($pA$) scattering at the LHC. It is based on the Gribov-Glauber model for the distribution over the number of inelastic collisions (wounded nucleons) combined with a parametrization of cross section (color) fluctuations in the projectile proton, which depend on the parton momentum fraction $x_p$, and the assumption of independent neutron emissions. We observe that while the effect of soft color fluctuations is modest, a reduction of the interaction strength with increasing $x_p$ provides the dominant effect. It allows us to qualitatively describe the trend of the ATLAS data on the ZDC energy spectra of forward neutrons emitted in dijet production in inelastic $pA$ scattering at $\sqrt{s_{NN}}=8.16$ TeV.

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M. Alvioli, V. Guzey, M. Strikman. 2025-04-10. Probing fluctuating protons using forward neutrons in soft and hard inelastic proton-nucleus scattering. https://arxiv.org/abs/2504.07514

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