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HK: Fachverband Physik der Hadronen und Kerne
HK 34: Hadron Structure and Spectroscopy IV
HK 34.2: Vortrag
Mittwoch, 12. März 2025, 17:45–18:00, HS 3 Physik
Understanding COMPASS data on π−+ p→ η(′)+π−+ p in the double-Regge region — •Henri Pekeler, David Spülbeck, and Bernhard Ketzer for the COMPASS collaboration — Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Germany
The COMPASS experiment at CERN’s SPS provides a very large data set to study the light-meson spectrum in several final states including η(′)π−, which is known to be the golden channel to investigate the lightest hybrid-meson candidate, the π1(1600). One challenge in the extraction of resonance parameters, like pole positions, is the separation of resonant and non-resonant processes.
To better constrain the non-resonant production mechanism of this final state, we analyse its high-mass region, i.e. 2.4 GeV<mη(′)π−<6 GeV using the double-Regge exchange model published by the JPAC collaboration. It was based on fits of published COMPASS data in the mass region below 3 GeV. By performing an event-based likelihood fit to the full COMPASS data set, we expand and test the model up to very high invariant masses. We find that by including the daughter trajectory of the a2, the a2′, the data can be fitted with only 8 free parameters. The relative strengths of the contributing amplitudes as well as the trajectory parameters for the a2′, determined by the fit, will be shown.
Supported by BMBF.
Keywords: COMPASS; meson spectroscopy; Double-Regge exchange