Mainz 2022 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 43: Hadron Structure and Spectroscopy VIII
HK 43.4: Talk
Wednesday, March 30, 2022, 15:00–15:15, HK-H9
Diffrectively produced f1(1285)π system in the reaction π−+p→π−π+π−η + p at 190 GeV/c from COMPASS — •David Spülbeck, Henri Pekeler, Mathias Wagner, Simon Havemann, and Bernhard Ketzer for the COMPASS collaboration — Helmholtz-Institut für Strahlen- und Kernphysik der Universität Bonn, Bonn, Germany
Hybrids are strongly interacting bound states with explicit gluonic degrees of freedom. Models and recent lattice QCD simulations alike predict the lightest hybrid state with spin-exotic quantum numbers 1−+ to have a strong branching into f1(1285)π. This particular decay can be studied well using the data recorded by the COMPASS collaboration on the scattering of a 190 GeV/c pion beam off a fixed hydrogen target. Selecting diffractive reactions of the kind π−+p→π−π+π−η + p yields the world’s largest data sample for a partial wave analysis that includes the f1(1285)π channel of interest. This contribution introduces the fundamental principles of the event selection for the π−π+π−η final state using COMPASS data. We discuss the selected data sample in detail and show the contributions of several resonances by identifying decay chains that end up in the four-body final state in question. A comparison to the data sample of the E852 collaboration will be made, which gave evidence for the spin-exotic state to decay into f1(1285)π. As the COMPASS data sample is about eight times larger, a PWA in bins of the 4-momentum transfer and the invariant mass will be possible, giving important constraints to disentangle resonant and non-resonant processes. Supported by BMBF.