Heidelberg 2015 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 56: Hadron Structure and Spectroscopy 11

HK 56.3: Vortrag

Donnerstag, 26. März 2015, 15:15–15:30, T/SR25

A new PWA method to extract dynamic amplitudes of two-particle subsystems embedded into multi-particle final states — •Fabian Krinner — Technische Universität München Physik-Department E18

Modern hadron spectroscopy experiments such as Compass have collected huge data sets of tens of millions of events. Therefore, analyses in spectroscopy are often dominated by systematic effects. A very common method to analyze these data is Partial-Wave Analysis (PWA). For more than two particles in the final state PWA usually assumes subsequent two-particle decays, i.e. the isobar model. Here, fixed mass shapes for the appearing intermediate states, the so-called isobars, have to be assumed. These shapes, which e.g. may be given by Breit-Wigner amplitudes, have to be put into the analysis beforehand and therefore may introduce a model dependence and thus increase systematic uncertainties. We present a new method, which allows to extract isobar shapes directly from the data in a more model-independent way. As a first application diffractively produced π⁻π⁺π⁻ events are analyzed and the validity and limitations of this method are shown via various Monte-Carlo studies. Since the method allows free isobar shapes, the effects of non-resonant contributions to the amplitude may also be studied. A common non-resonant contribution is the Deck effect, for which the effective isobar shapes introduced by partial-wave projections decomposing its intensity will be presented.