Measuring two-hadron azimuthal asymmetries on a longitudinally polarized proton target

In recent years, measuring azimuthal asymmetries on polarized targets emerged as a powerful tool to investigate the nucleon spin structure, one of the main goals of the COMPASS physics program. COMPASS is a fixed target experiment, located at the SPS/CERN and is characterized by a two-stage spectrometer with large acceptance and excellent particle identification. By scattering a tertiary longitudinally polarized μ⁺ beam on a transversely or longitudinally polarized ammonia target, it suits the experimental requirements for asymmetry measurements. Two-hadron azimuthal asymmetries were already studied at COMPASS using transversely polarized protons. In this talk we present first measurements of two-hadron azimuthal asymmetries scattering a 160 GeV/c, respectively 200 GeV/c, μ⁺ beam off longitudinally polarized protons.