During the 2008 COMPASS data taking an unprecedented statistical precision has been reached in peripheral interactions of 190 GeV/c pions with a proton target leading to the π
-π
-π
+ final state. A spin-parity analysis in the kinematical region of the squared four-momentum transfer 0.1 ≤ t' ≤ 1.0 GeV
2/c
2 was carried out based on a model of 88 partial waves. Besides the precise determination of properties of known resonances, a new axial-vector state, the a
1(1420), was observed for the first time.
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During the 2008 COMPASS data taking an unprecedented statistical precision has been reached in peripheral interactions of 190 GeV/c pions with a proton target leading to the π
-π
-π
+ final state. A spin-parity analysis in the kinematical region of the squared four-momentum transfer 0.1 ≤ t' ≤ 1.0 GeV
2/c
2 was carried out based on a model of 88 partial waves. Besides the precise determination of properties of known resonances, a new axial-vector state, the a
1(1420), was observed for the first ti...
»