EMC studies using the simulation framework of PANDA

The Anti-Proton ANnihilation at DArmstadt (PANDA) experiment proposed at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt (Germany) will perform a high precision spectroscopy of charmonium and exotic hadrons, such as hybrids, glueballs and hypernuclei. A highly intense beam of anti-protons provided by High Energy Storage Ring (HESR) with an unprecedented resolution will scan a mass range of 2 to 5.5 GeV/c2. In preparation for experiments with PANDA, careful and large-scale simulation studies need to be performed in the coming years to determine analysis strategies, to provide feedback for the design, construction and performance optimization of individual detector components and to design methods for the calibration and interpretation of the experimental results. Results of a simulation for the ElectroMagnetic Calorimeter (EMC), built from lead tungstate (PWO) crystals and placed inside the Target Spectrometer (TS), are presented. The simulations were carried out using the PandaRoot framework, which is based on ROOT and being developed by the PANDA collaboration.

💡 Research Summary

The paper presents a comprehensive simulation study of the Electromagnetic Calorimeter (EMC) that will be installed inside the Target Spectrometer of the PANDA experiment at the FAIR facility. PANDA aims to perform high‑precision spectroscopy of charmonium states and exotic hadrons (hybrids, glueballs, hypernuclei) in the mass range 2–5.5 GeV/c² using a high‑intensity, high‑resolution antiproton beam from the High Energy Storage Ring (HESR). Because the physics goals demand excellent energy and time resolution, the EMC—built from lead‑tungstate (PbWO₄, PWO) crystals—must be carefully optimized and its performance thoroughly validated before data taking.

The authors used the PandaRoot software framework, which integrates ROOT and GEANT4, to model the full detector geometry, material properties, and read‑out chain. The simulated EMC consists of more than 1,800 PWO crystals, each 2 × 2 × 20 cm³, arranged to cover polar angles from 0° to 140°. The simulation incorporates realistic temperature dependence of the crystal light yield (‑0.3 % / °C), the behavior of avalanche photodiodes (APDs) operated at 400 V, electronic noise (≈1 MeV RMS), and the digitization performed by the front‑end electronics. The QGSP_BERT physics list was chosen to describe hadronic interactions, while electromagnetic processes were treated with the standard GEANT4 EM models.

Key performance metrics extracted from the simulated data are:
• Energy resolution ΔE/E = (1.5 % ⊕ 0.5 % / √E