Search for $\pi_1(1600)$ in a three-pion system at GlueX

by Ilia Belov

Tuesday Jul 21, 2026, 3:00 PM → 3:45 PM Europe/Zurich

NB2/158 (RUB)

Abstract:

The GlueX experiment in Hall D at Jefferson Lab is designed for studies
of the light meson spectrum with an emphasis on searches for hybrid
mesons that have exotic quantum numbers and therefore cannot be
classified as conventional hadrons. Advanced searches for spin-parity
exotic mesons are performed through the application of Partial Wave
Analysis (PWA) techniques.
In this talk, I present the search for the $\pi_1(1600)$ meson with
$1^{-+}$ quantum numbers by means of the PWA of the $\pi^{+}\pi^{-}\pi^{-}$ 
system produced in the $\gamma\,p\to\pi^{+}\pi^{-}\pi^{-}\Delta^{++}(\to p\pi^{+})$ reaction.
In the approximation of an isobar decay, data with the selected three-pion
final states are fitted as coherent sums of partial-wave amplitudes
defined in the reflectivity basis. The PWA techniques are applied in
bins of $m(3\pi)$ allowing to extract the overall $m(3\pi)$ lineshape
for each of the model contributions. The main interest lies in
establishing the existence of a resonant $1^{-+}$ contribution in the
$P$-wave $\rho\,\pi^{-}$ and $D$-wave $f_{2}\,\pi^{-}$ configurations.

Seminar_40min.pdf