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arXiv · 1109.1789

Diffractive Dissociation into π- π- π+ Final States at COMPASS

Florian Haas
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Abstract

Diffractive dissociation reactions studied at the COMPASS experiment at CERN provide access to the light-meson spectrum. During a pilot run in 2004, using a pion beam and a lead target, 420k π- π- π+ final-state events with masses below 2.5 GeV/c2 were recorded, yielding a significant spin-exotic signal for the controversial π1(1600) resonance. After a significant upgrade of the spectrometer in 2007, the following two years were dedicated to meson spectroscopy. Using again a pion beam, but now with a liquid hydrogen target, an unique statistics of ~60M events of the same final state was gathered in 2008. During a short campaign in 2009, the H2 target was exchanged by several solid state targets in order to compare final states produced on targets with different atomic numbers. A partial-wave Analysis (PWA) was performed on all these data sets and results are presented.

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Florian Haas. 2011-12-15. Diffractive Dissociation into π- π- π+ Final States at COMPASS. https://doi.org/10.1063/1.3647141

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