Observation of a $J^{PC}=1^{-+}$ exotic signal in the $\pi^{-}\pi^{0}\pi^{0}$ system diffractively produced at COMPASS, and comparison to the charged decay mode - INSPIRE

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Observation of a $J^{PC}=1^{-+}$ exotic signal in the $\pi^{-}\pi^{0}\pi^{0}$ system diffractively produced at COMPASS, and comparison to the charged decay mode

COMPASS

Collaboration

•

Frank Nerling
(
- Freiburg U. and
- CERN
)

for the collaboration.

Aug, 2012

4 pages

Part of Proceedings, 12th International Workshop on Production, properties and interaction of mesons (MESON 2012) : Cracow, Poland, May 31-June 5, 2012

Published in:

EPJ Web Conf. 37 (2012) 09025

Contribution to:

- MESON 2012

e-Print:

1208.0474 [hep-ex]

DOI:

10.1051/epjconf/20123709025

Experiments:

CERN-SPS-NA58

View in:

reference search6 citations

Citations per year

Abstract: (arXiv)

The COMPASS experiment at the CERN SPS features good charged particle tracking and coverage by electromagnetic calorimetry, and our data provide excellent opportunity for simultaneous observation of new states in two different decay modes within the same experiment. The existence of the spin-exotic

\pi_1(1600)

resonance in the

\rho\pi

decay channel is studied for the first time in COMPASS in both decay modes of the diffractively produced

(3\pi)^{-}

system:

\pi^{-}p \rightarrow \pi^{-}\pi^{0}\pi^{0}p

and

\pi^{-}p \rightarrow \pi^{-}\pi^{+}\pi^{-}p

. A preliminary partial-wave analysis (PWA) performed on the 2008 proton target data allows for a first conclusive comparison of both

(3\pi)^{-}

decay modes not only for main waves but also for small ones, including the spin-exotic

1^{-+}

wave. We find the neutral versus charged mode results in good agreement with expectations from isospin symmetry. Both, the intensities and the relative phases to well-known resonances, are consistent for the neutral and the charged decay modes of the

(3\pi)^{-}

system. The status on the search for the spin-exotic

\pi_1(1600)

resonance produced on a proton target is discussed.

Note:

4 pages, 18 figures, MESON2012 Conference Proceedings, to appear in the proceedings of the 12th International Workshop on Meson Production, Properties and Interaction, KRAK\'OW, POLAND, 31 May - 5 June 2012

pi1(1600)
final state: (3pi)
isospin: symmetry
decay modes
COMPASS
diffraction
partial wave analysis
quantum number

References(10)

Figures(17)

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