Speaker
Description
COMPASS is a multi-purpose fixed-target experiment at the CERN SPS. One of its main goals is to probe
the strong interaction at low energies by studying the excitation spectrum of light mesons in diffractive scattering reactions of a $190\ \text{GeV}/c$ hadron beam on a proton target.
This is done by decomposing the data into partial-wave amplitudes with well-defined quantum numbers and searching for resonances in these amplitudes.
We have collected the world's largest datasets of various final states.
First and foremost, COMPASS' flagship $\pi^-\pi^-\pi^+$ channel has allowed high-precision measurements of many light mesons.
New analyses of final states with kaons complement their findings. After briefly presenting the analysis method, we will discuss measurements in the $\mathrm{K}_S^0 \mathrm{K}^-$ final state, which gives access exclusively to $a_J$ mesons at higher invariant masses.
COMPASS has also contributed significantly in the search for exotic (non-$q\bar{q}$) mesons. We will present novel analyses of the $\omega\pi^-\pi^0$ and $\pi^-\pi^-\pi^+\eta$ final states, which are especially interesting as the lightest hybrid meson is predicted to decay into both of these final states.
Taking advantage of the kaon fraction of the beam, the COMPASS analysis of the $\mathrm{K}^-\pi^-\pi^+$ final state has given insight into the lesser known strange-meson spectrum.
These efforts will be continued in the AMBER experiment via
its planned strange-meson spectroscopy programme.
The COMPASS data also allows for measurements beyond spectroscopy. We will discuss one such analysis of the non-resonant double-Regge exchange process, done in collaboration with JPAC.
