Blue Waters Symposium 2019

COMPASS probes proton substructure by scattering high-energy pion- and muon-beams on nuclear targets at CERN. The experiment explores the momentum and coordinate phase space of quarks inside the proton. Observing correlations between proton spin and the intrinsic transverse momentum of quarks will shed light on the quark dynamics inside the proton and will provide a critical test of fundamental predictions derived from Quantum Chromo Dynamics, the quantum field theory describing the strong nuclear force. The measurements produce 10 petabytes of experimental and simulated data. Blue Waters' balance of processing capabilities and data storage and handling is well suited for the analysis of the large COMPASS data samples as these require significant algorithmic processing per pion/muon-proton scattering event. In addition to raw data processing and physics-level analysis, COMPASS carries out extensive studies of systematic effects as Blue Waters allows for a detailed simulation of COMPASS detector and environmental properties.