Application of FHCal for Heavy-Ion Collision Centrality Determination in MPD/NICA Experiment

Vadim Volkov,Sultan Musin,Marina Golubeva,Fedor Guber,Alexander Strizhak,Nikolay Karpushkin,Alexander Ivashkin,Sergey Morozov

doi:10.3390/particles4020022

Vadim Volkov, Sultan Musin + Show 6 more

Open Access

https://doi.org/10.3390/particles4020022

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Abstract

Two approaches related to the centrality determination in heavy-ion Multi-Purpose Detector (MPD) experiments, using charge-particles multiplicity in Time Projection Chamber (TPC) and the energy deposition in Forward Hadron Calorimeter (FHCal) are discussed. The main features of the FHCal are the fine transverse segmentation and the beam holes in the center of the calorimeters. Leaking the heavy non-interacting fragments (spectators) leads to ambiguity in the dependence of energy deposition in the FHCal on the collision centrality. However, the calorimeter transverse segmentation allows one to measure the energy distributions in each of the FHCal modules and to construct combined observables to resolve the problems associated with the beam hole. The comparison of these approaches in the collision centrality measurements is discussed.

Highlights

The centrality is the global observable determining the geometry of the nucleus– nucleus collision for the event characterization
The Glauber Monte Carlo codes are used to evaluate the number of participants from the particle multiplicity in the tracking detectors [1,2]
The Multi-Purpose Detector (MPD) experiment at NICA accelerator complex [4] has both options for the determination of the collision centrality

Summary

Introduction

The centrality is the global observable determining the geometry of the nucleus– nucleus collision for the event characterization. The measurements of centrality can be performed with participants or spectators of colliding nuclei. The charged-particle multiplicity allows the number of participants to be estimated.

Results

Conclusion