Speaker
Description
A precise and complete measurement of the excitation spectrum of light mesons allows us to study QCD in the non-perturbative regime and is an important input to other studies, e.g., of $B$ meson decays. While the non-strange light-meson spectrum is already mapped out rather well, the strange-meson spectrum may hold many surprises, as almost no new data have been available for the last 20 years.
The $190\,\mathrm{GeV}/c$ negative hadron beam at CERN's M2 beam line contains a $K^-$ component, which allows us to study the spectrum of strange mesons with the COMPASS experiment, a two-stage magnetic spectrometer. The flagship channel is the $K^-\pi^-\pi^+$ final state, for which COMPASS has acquired the so-far world's largest data set. We performed a partial-wave analysis in order to disentangle the produced mesons by their spin-parity quantum numbers. In this talk, we will discuss major challenges of this analysis such as the treatment of incoherent backgrounds and report on properties of excited strange mesons with various spin-parity quantum numbers.
