Speaker
Description
The research program of the SPD experiment at NICA facility is focused on studies of collisions of polarized protons and deuterons [1,2]. Studies of collisions of non-polarized light nuclei, 12C and 40Ca, are also considered as a possible extension of the SPD research program [3]. The SPD setup will be equipped with a pair of Zero Degree Calorimeters (ZDC) for luminosity measurements and local polarimetry with forward neutrons. In studies of 12C-12C and 40Ca-40Ca collisions, ZDC can be employed to detect forward spectator neutrons as event triggers and determine the collision centrality. However, as it was demonstrated [4], the short-range nucleon-nucleon correlations in colliding nuclei can significantly change the yields of the spectator neutrons. It was also shown that accounting for intranuclear clustering decreases the yield of spectator neutrons [5].
In this work, 12C-12C and 40Ca-40Ca collisions at the SPD were simulated with the Abrasion-Ablation Monte Carlo for Colliders (AAMCC-MST) model with MST-clustering [4-7], which was validated for fragmentation of 16O [5,6]. In order to study the effect of α-clustering in 12С, the nuclear density profile of 12С was parametrized either as three α-clusters arranged into a triangle [8] or by the harmonic oscillator parametrisation. The short-range nucleon-nucleon correlations (SRC) in 12C and 40Ca were taken into account following Ref. [9]. The yields of forward spectator neutrons were calculated for 12C-12C and 40Ca-40Ca collisions at √sNN = 11 GeV. The centrality dependence of the neutron yields was proposed as a possible probe of the SRC in 40Ca and α-clustering in 12C. The obtained results can help in evaluating the performance of neutron ZDCs in future nucleus-nucleus runs at the SPD.
References
[1] V. Abazov et al., (SPD Collaboration), Natural Sci. Rev. 1, 1 (2024)
[2] V. Abazov et al., (SPD Collaboration), arXiv:2102.00442 (2021)
[3] V. Abramov et al., Phys. Part. Nucl. 52, 1044 (2021)
[4] N. Kozyrev et al., Eur. Phys. J. A 58, 184 (2022)
[5] A. Svetlichnyi et al., Physics 5, 381 (2023)
[6] A. Svetlichnyi et al., Phys. Atom. Nucl. 85 985 (2022)
[7] R. Nepeivoda et al., Particles 5, 40 (2022)
[8] W. von Oertzen et al., Phys. Reports 432, 43 (2006)
[9] M. Alvioli et al., Phys. Rev. Lett. B 680, 225 (2009)
