Speaker
Description
The COMPASS experiment is a multi-purpose fixed-target experiment at the CERN SPS. Part of its physics program is the study of non-strange light mesons produced via diffractive scattering of $190\,\mathrm{GeV}/c$ $\pi^{-}$ off a liquid-hydrogen target. This gives access to the excitation spectrum of all isovector mesons $a_J$ and $\pi_J$ in multiple final states. The spin-exotic meson $\pi_1(1600)$ is of particular interest.
COMPASS observed the $\pi_1(1600)$ in the $\pi^{-}\pi^{-}\pi^{+}$, $\eta\pi^{-}$, and $\eta'\pi^{-}$ final states. However, based on lattice QCD predictions the $\pi_1(1600)$ is expected to dominantly decay to $b_1(1235)\pi$. This decay mode is studied in the $\omega(782)\pi^{-}\pi^{0}$ final state, for which COMPASS acquired the largest dataset. We disentangle contributing meson resonances in a partial-wave analysis and find clear indications for a resonance-like signal in this final state consistent with the $\pi_1(1600)$. In this talk, we will discuss recent results of non-strange light-meson spectroscopy at COMPASS with focus on the $\omega(782)\pi^{-}\pi^{0}$ final state.
