Event plane determination from the zero degree calorimeter at the cooling storage ring external-target experiment

The Cooling Storage Ring external-target experiment (CEE) spectrometer is used to study the nuclear matter created in heavy-ion collisions at vs(NN )= 2.1-2.4 GeV with the aim to reveal the quantum chromodynamics phase structure in the high-baryon-density region. Collective flow is considered an effective probe for evaluating the properties of media during high-energy nuclear collisions. One of the main functions of the zero-degree calorimeter (ZDC), a subdetector system in the CEE, is to determine the reaction plane in heavy-ion collisions. This step is crucial for measuring the collective flow and other reaction-plane-related analyses. In this paper, we illustrate the procedures for event plane determination using the ZDC. Finally, isospin-dependent quantum molecular dynamics model-based predictions of the rapidity dependence of the directed and elliptical flows for p, d, t, He-3, and He-4, produced in 2.1 GeV U + U collisions, are presented.

Automated summary

The Cooling Storage Ring external-target experiment (CEE) uses a spectrometer to study nuclear matter in heavy-ion collisions and aims to understand the phase structure of quantum chromodynamics in high-baryon-density region. Collective flow is used as a probe to evaluate the properties of the media during these collisions. The zero-degree calorimeter (ZDC) in the CEE plays a crucial role in determining the reaction plane, which is important for measuring the collective flow and other related analyses. This paper presents the procedures for event plane determination using the ZDC and provides predictions of the rapidity dependence of directed and elliptical flows based on an isospin-dependent quantum molecular dynamics model in 2.1 GeV U + U collisions.