Exotic meson $\pi_1(1600)$ with $J^{PC} = 1^{-+}$ and its decay into $\rho(770)\pi$

Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Augsten, K.; Augustyniak, W.; Azevedo, C.D.R.; Badelek, B.; Balestra, F.

doi:10.1103/PhysRevD.105.012005

Exotic meson $\pi_1(1600)$ with $J^{PC} = 1^{-+}$ and its decay into $\rho(770)\pi$

COMPASS

Collaboration

Aug 3, 2021

30 pages

Published in:

Phys.Rev.D 105 (2022) 1, 012005

Published: Jan 1, 2022

e-Print:

2108.01744 [hep-ex]

DOI:

10.1103/PhysRevD.105.012005 (publication)

Report number:

CERN-EP-2021–162

Experiments:

CERN-SPS-NA58

View in:

pdfdatasets

reference search27 citations

Citations per year

Abstract: (APS)

We study the spin-exotic

J^{P C} = 1^{- +}

amplitude in single-diffractive dissociation of

190 GeV / c

pions into

π^{-} π^{-} π^{+}

using a hydrogen target and confirm the

π_{1} (1600) \to ρ (770) π

amplitude, which interferes with a nonresonant

1^{- +}

amplitude. We demonstrate that conflicting conclusions from previous studies on these amplitudes can be attributed to different analysis models and different treatment of the dependence of the amplitudes on the squared four-momentum transfer and we thus reconcile these experimental findings. We study the nonresonant contributions to the

π^{-} π^{-} π^{+}

final state using pseudodata generated on the basis of a Deck model. Subjecting pseudodata and real data to the same partial-wave analysis, we find good agreement concerning the spectral shape and its dependence on the squared four-momentum transfer for the

J^{P C} = 1^{- +}

amplitude and also for amplitudes with other

J^{P C}

quantum numbers. We investigate for the first time the amplitude of the

π^{-} π^{+}

subsystem with

J^{P C} = 1^{- -}

in the

3 π

amplitude with

J^{P C} = 1^{- +}

employing the novel freed-isobar analysis scheme. We reveal this

π^{-} π^{+}

amplitude to be dominated by the

ρ (770)

for both the

π_{1} (1600)

and the nonresonant contribution. These findings largely confirm the underlying assumptions for the isobar model used in all previous partial-wave analyses addressing the

J^{P C} = 1^{- +}

amplitude.

11.80.Et
13.25.Jx
13.85.Hd
14.40.Be
hydrogen: target
meson: exotic
rho(770)
spectral
partial wave analysis
pi1(1600)

References(0)

Figures(38)

Loading ...

Exotic meson π1(1600)\pi_1(1600)π1​(1600) with JPC=1−+J^{PC} = 1^{-+}JPC=1−+ and its decay into ρ(770)π\rho(770)\piρ(770)π

Citations per year

Exotic meson $\pi_1(1600)$ with $J^{PC} = 1^{-+}$ and its decay into $\rho(770)\pi$