Studies of light mesons at COMPASS
Technische Universität München, James-Franck-Straße, 85748 Garching, Germany
a e-mail: email@example.com
b The author acknowledges support by the German Bundesministerium für Bildung und Forschung (BMBF), by the Maier-Leibnitz-Laboratorium der Universität und der Technischen Universität München, by the DFG Cluster of Excellence “Origin and Structure of the Universe” (Exc153), and by the computing facilities of the Computational Center for Particle and Astrophysics (C2PAP).
Published online: 5 December 2017
To investigate the spectrum of light mesons, the COMPASS experiment has recorded data with a 190 GeV/c negative pion beam impinging on a liquid hydrogen target. Diffractive dissociation reactions at squared four-momentum transfers to the target between 0.1 and 1.0 (GeV/c)2 are studied. The flagship channel is the π− π+ π− final state, for which COMPASS has recorded the at present world’s largest data sample. A new axial-vector signal, the a1(1420), has been found with unusual properties, pointing to an exotic nature. The findings are confirmed by the analysis of theπ− π0 π0 final state.
© The Authors, published by EDP Sciences, 2017
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