JPS Conf. Proc. 13, 010018 (2017) [9 pages]
Proceedings of the 14th International Conference on Meson-Nucleon Physics and the Structure of the Nucleon (MENU2016)
The Spectrum of Light Isovector Mesons with C = +1 from the COMPASS Experiment
* for the COMPASS Collaboration
Physik Department, Technical University Munich, James Franck Str., 85748 Garching, Germany
Received October 5, 2016

Based on the largest event sample of diffractively produced πππ+, obtained by a pion beam of 190 GeV/c momentum, the COMPASS collaboration has performed the so far most advanced partial-wave analysis on multi-body final states, using the isobar model. The large number of 88waves included in the analysis reduces truncation effects. We have used fourteen waves, to extract resonance parameters for eleven light-meson candidates, most of them observed previously. The coherence of the analysis and the large variety of systematic studies has allowed us to determine mass and width of most aJ and πJ states with a total of six different values of JPC below a mass of 2:1 GeV/c2, with high confidence. We exploit that the production rates of resonant and non-resonant contributions in these fourteen waves vary differently with the four-momentum transfer squared in the reaction. In addition, we have performed the first isobar-freed analysis in diffraction, from which we have determined the shape of the ππ S-wave isobar for different JPC of the 3π system.

©2017 The Physical Society of Japan

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