Sonderseminar Tobias Stockmanns (FZ Jülich)

A Precision Window to QCD Charmonium Physics at the Future PANDA Detector

Abstract:

Quantum Chromo Dynamics (QCD) is the generally accepted theory to describe the Strong Force which binds quarks and forms hadrons. The theory has been tested to high precision for short distances and high momentum transfers. However, for longer distances the calculations get increasingly more complicated as new phenomena like the confinement of quarks arise.

This regime corresponds to the transition between perturbative and non-perturbative QCD. Here, the detailed study of the charmonium spectrum could play the same role that the positronium spectrum played for Quantum Electrodynamics.

In fact, new and unexpected states in the charmonium spectrum have been found where at least some states are composed of more than the conventional two valence quarks. A number of different theories exist to explain the configuration of the new exotic states. However, an experimental proof, compatible with one of the theories, has yet to be found.

One way to distinguish between theories is the precision measurement of the width and the line shape of the states. The measurements however require a resolution which is an order of magnitude better than is accomplished in existing experiments.

The PANDA experiment, together with the antiproton accelerator HESR at the future Facility for Antiproton and Ion Research (FAIR), will provide the resolution needed for high precision studies of the charmonium spectrum and the new exotic states.

A key component of the PANDA detector in charmonium physics is the Micro Vertex Detector, enabling the observation of tracks of charged particles directly around the interaction point with a resolution sufficient to identify open charm particles by their flight path of a couple of 100 microns.

Due to the similarity of signal and background events no easy selection of signals is possible and PANDA has to process the complete detector data online at the same rate as it is produced in the experiment (up to 200 GByte/s). Based on the calculations, only every 1000th event will be selected for permanent storage and offline analysis. To achieve the required speed, high performance tracking algorithms and a high degree of parallel processing is needed.

This presentation will present the experimental status, the technological challenges, and the objective of the PANDA experiment to shed new light on the charmonium spectrum and the charmonium-like new particles.

 

Hörsaal HISKP, Raum 0.023

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