UIUC COMPASS group unravels proton quark structure using Frontera supercomputer

By C. Riedl
January 5, 2021

After the successful completion of the COMPASS data-production project on the local supercomputer Blue Waters in late 2019, we moved our productions in 2020 to the next-generation NSF-funded supercomputer Frontera at the Texas Advanced Computing Center (TACC). The COMPASS experiment at CERN uses nuclear-polarized targets and pion or polarized muon beams to study proton structure including transverse momentum dependent (TMD) degrees of freedom and generalized parton distributions (GPDs). The raw TMD- and GPD-related COMPASS data, which had previously been transferred from CERN, were moved bundled in tar archives from Blue Waters to Frontera using the Globus Online service.

    Our team - Research Assistant Professor Caroline Riedl, postdocs Vincent Andrieux and Riccardo Longo, graduate students April Townsend and Gregory Mattson, Professor Matthias Grosse Perdekamp - and some collaborators from COMPASS convert the raw experimental data into a format that can be used for high-level physics analysis, extract high-precision detector efficiency maps from the data, and perform detailed simulations on Frontera. The resulting output is transferred to CERN and made available to the COMPASS analysis group. Productions are started upon request by the COMPASS Analysis Coordinator Vincent Andrieux. Frontera allows to process the data in a significantly faster way than would be possible at CERN and even at Blue Waters. Our current Leadership Resource Allocation amounts to 1.5 million Frontera node hours.                                              
Our project was in June 2020 featured in the TACC article "Cracking Open the Proton"