Probing Short-Range Nucleon–Nucleon Correlations by Detecting Spectator Neutrons in Collider Experiments

We investigate whether short-range nucleon–nucleon correlations (NN-SRC) and cluster configurations in nuclei can be explored by studying spectator neutrons produced in high-energy nucleus–nucleus collisions. In particular, we propose to measure the multiplicity distributions of forward spectator neutrons in symmetric 12C–12C and 40Ca–40Ca collisions at sNN=11 GeV with the Spin Physics Detector (SPD) at the NICA facility. To assess this method, we simulate the production of spectator nucleons in these reactions using the Abrasion–Ablation Monte Carlo for Colliders model with MST clustering (AAMCC-MST). Short-range nucleon–nucleon correlations inside 12C and 40Ca are implemented via a Monte Carlo rejection sampling procedure. Our results indicate that spectator production exhibits only a weak dependence on the specific features of NN-SRC. We also observe that including α-cluster configurations in 12C leads to a reduction of the average multiplicity of spectator neutrons as a function of collision centrality.