Narrow Results

Fundamental questions concerning the strong interaction are addressed by the PANDA experiment at the future FAIR facility at GSI-Darmstadt. PANDA will be a general purpose detector of modular design optimized to measure the interaction of an antiproton beam with proton and heavy nuclear targets. The physics program at PANDA covers a wide range of topics including gluonic excitations, spectroscopy of strange and charm mesons, Drell-Yan and CP violating processes. This contribution focuses on the part of the physics program dealing with antiproton - proton annihilation.

The PANDA experiment at FAIR comprises the possibility to study antiproton annihilations on nuclear targets. Such reactions are ideally suited to investigate the in-medium-potential of hadrons – charmed mesons, charmonium, antikaons, antibaryons – making use of the PANDA detector system to detect the final state particles. The paper discusses connected experimental results, predictions i.a. for the so far unexplored region of the charm quark mass, and the intended experimental procedure.

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 optimisation 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.

The PANDA detector will allow to investigate the charmonium region in annihilation processes at a energy range for which production cross sections of charmonium states are unknown, in particular for those above the threshold. Cross sections for these states are expected to be rather small, so that it has to be verified that PANDA can cope with small rates. Therefore, several reaction channels have been identified as "benchmark channels" and the PANDA performance has been investigated in Monte Carlo studies. The focus of the charmed benchmark channels is to show the physics performance of the planned apparatus and to investigate the feasibility of separating the physics signal from a huge hadronic background.

PANDA is a future antiproton experiment designed to study fundamental questions of hadron and nuclear physics. It will work as a fixed-target facility, hence – due to the Lorentz boost – the distribution of reaction products will be strongly forward-peaked, in particular for the near-threshold measurements. Thus, the Forward Spectrometer, covering the most forward angles (θ_lab < 10°) is one of the key components of PANDA.

In this contribution, current design of the Forward Spectrometer is presented. Spectrometer components, including dipole magnet, tracking detectors, electromagnetic and hadron calorimeter, muon counters, RICH detector and TOF system are discussed. Results of simulations are shown along with tests of the prototype detectors performed in a high-rate environment.

The study of the charmonium system is a powerful tool to understand the strong interaction. In annihilations studied with , the mass and width of the charmonium state, such as h_c, will be measured with an excellent accuracy, determined by the very precise knowledge of the beam resolution and not limited by the resolution of the detector. The analysis of h_c demonstrates the feasibility to accurately determine a specific final state in the spectrum of charmed mesons. The preliminary background analysis of the decay competing with a signal channel is under control. A comparison of three decay modes of charmonium h_c via the electromagnetic transition is presented.

On October 4th, 2010, nine countries signed the international agreement on the construction of the Facility for Antiproton and Ion Research FAIR. The new facility is going to be constructed within the next eight years adjacent to the existing accelerator complex of the GSI Helmholtz Centre for Heavy Ion Research at Darmstadt/Germany, expanding the research goals and technical possibilities substantially. Providing a broad spectrum of unprecedented fore-front research at worldwide unique accelerator and experimental facilities, FAIR will open the way for a large variety of experiments in hadron, nuclear, atomic and plasma physics as well as applied sciences which will be briefly described in this article.

As of the year 2018 the Facility for Antiproton and Ion Research (FAIR) will offer access to exotic ion beams and beams of antiproton of unprecedented luminosity. The facility currently under construction in Darmstadt, Germany, adjacent to the existing accelerator at the GSI Helmholtz Centre for Heavy-Ion Research, will serve several collaborations and fields simultaneously: atomic, hadron, nuclear, and plasma physics.