Hadron Spektroskopy at GSI
The existence of non conventional hadrons (e.g. mesons with more than a quark-antiquark pair) is one of the most pressing questions in the QCD of bound states. High statistics experiments (like PANDA) with unprecedented resolution are the key for their discovery. The online and offline selection of hadron decays is the tool of choice to unravel the final state composition and therefore to identify and understand the very states involved in the process.
Since simple cut-and-count apporaches are unable to reveal the complicated features created by mixing of states and the facets of quantum mechanics, it is mandatory to analyze the final states in terms of an amplitude analysis (often called partial wave analysis), where the complex amplitudes - leading to the complicated decay patterns - are analyzed and fitted to the data to identify states and their static and dynamic properties.
Modern hadronic experiments yield enormous interaction rates and most of what is contained in the data stream is not the prime focus of the experiment. This is also true for PANDA. The yield of potentially interesting events is several orders of magnitude smaller than a minimum bias data set. Thus it is important to preselect events already online to reduce the load for later offline processing.
Difficulties to achieve a large background rejection and an excellent efficiency for golden channels often arise from the rudimentary calibration and from the fact that signal and background may look alike. Finding efficient and decisive observables is the key for this research branch.
Prospektive Analysis for PANDA
The frontier of hadron physics and the most interesting questions are a moving target, with new questons arising from solving others. Thus it is important to stay up to date with the physics programme as a whole and in particular in the first physics in the first years of operation. To investigate and validate the physics reach and richness of interesting topics of the planned PANDA experiment is an important topic for our spectroscopy group to keep the focus in PANDA modern and attractive.
Data Analysis for BES3 and GlueX
Hadrons at GSI is member of BES3 and GlueX, which are active experiments at IHEP Beijing, China and Jefferson Lab, Newport News, USA. Our analyses focuses on flavored exotic hadrons. At BES3 the focus is on charmed hadrons and at GlueX on strange quarks. Please see the pages of the respective experiments (BESIII/GlueX) for more details.
Teaching and Service to the Science community
Summer schools, workshops, web pages and other educational elements are vital tools to prepare for the future, for new discoveries and a deeper understanding of quark binding and exotic and conventional bound hadrons. Hadrons at GSI is co-leading the world-wide effort to train students in partial wave analysis. The latest summer school was jointly organized together with the Helmholtz-Institute Mainz.