Bochum 2018 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 30: Hadron Structure and Spectroscopy V
HK 30.3: Vortrag
Mittwoch, 28. Februar 2018, 14:45–15:00, HZO 50
The axial-vector a1(1420) as a triangle singularity — •Mathias Wagner, Mikhail Mikhasenko, and Bernhard Ketzer for the COMPASS collaboration — Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn, Germany
The a1(1420), a resonance-like signal, was recently observed by the COMPASS experiment in the JPC=1++ partial wave decaying to f0(980)π. Fitting a Breit-Wigner form to the spin-density matrix, a mass of 1414−13+15 MeV and a width of 153−23+8 MeV was extracted [Phys.Rev.Lett. 115 (2015) no.8, 082001].
This talk focuses on the results of applying a new fit model to the data, in which the a1(1420) is interpreted as a triangle singularity appearing in the rescattering of K*K→ f0π. I will explain the fit model and discuss the fit results as well as its statistical uncertainties obtained by applying a bootstrap method. Also the results of systematic studies are presented. The quality of the triangle fit will be compared to the simple Breit-Wigner model.
Supported by BMBF.