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Summer 2020 through Fall 2021
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January 2021
UIUC sPHENIX group successfully completes pre-production of EMCal absorber blocks

sPHENIX is an experiment at Brookhaven National Lab designed to study the microscopic properties of the quark gluon plasma with also some cold QCD potential. The experiment is scheduled to see first beam in 2023 and will take data through at least 2025, until the final preparations for the Electron Ion Collider will shut down RHIC. The UIUC Nuclear Physics group is in charge of building the absorber blocks for the sPHENIX electromagnetic calorimeter (EMCal). The blocks are shipped to our collaborators at BNL, where they are equipped with light guides and SiPMs and glued into sectors of 96 blocks each. The technicians and students at NPL completed the pre-production stage of the project in late October 2020 by constructing 1,152 EMCal blocks. Since then the production stage is in full swing, with almost 4,000 blocks to be delivered to BNL. A block is made from an assembly of 2,668 scintillating fibers in a tungsten-epoxy matrix and is machined to high precision on all sides. While the fiber assemblies are prepared by undergrad students, the blocks are produced by our technician team at the Nuclear Physics Lab: Adam Wehe, Saad Altaf, several part-time technical helpers, and senior tech Eric Thorsland.

Each block is tested by undergrad students for light transmission, scintillation, dimensions, and density before sending it to BNL. As of the end of 2020, 60 UIUC undergrad students have worked with us on this project! The block testing and grading is coordinated by grad students (Anabel Romero Hernandez, Xiaoning Wang, Adin Hrnjic) and supervised by postdoc Tim Rinn. Research Assistant Professor Caroline Riedl is the corresponding level-3 manager with BNL and Associate Professor Anne Sickles is the PI.

The group tested several EMCal prototype blocks in a test beam at Fermilab in 2018. The analysis of the data was led by grad student Anabel Romero Hernandez and postdoc Tim Rinn. The findings from the test-beam data demonstrated that the energy resolution of the prototype satisfies the sPHENIX requirements for electron / hadron separation and they were published here. (and accepted by IEEE TNS).

January 2021
UIUC COMPASS group unravels proton quark structure using Frontera supercomputer

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"

October 2020
ICASU Welcomes New Graduate Fellow

The Illinois Center for Advanced Studies of the Universe (ICASU) welcomes the first ICASU graduate fellow, Debora Mroczek. Debora joins Professor Jacquelyn Noronha-Hostler’s research group, where she will use machine learning to map the Quantum Chromodynamic (QCD) phase diagram.

October 2020
Publishing During the Pandemic

PhD student Travis Dore and Assistant Professor Jaki Noronha-Hostler wrote a paper on the effects of shear and bulk viscosity and their influence on the search for the Quantum Chromodynamics critical point. We used relativistic hydrodynamics and studied at what point hydrodynamics breaks down as one approaches a critical point and also how out out-of-equilibrium effects influence the search for the critical point. This was recently accepted for publication in Phys. Rev. D:

PhD student Patrick Carzon and former Postdoc Dr. Matt Sievert (who recently left for a professorship at New Mexico State University) and Assistant Professor Jaki Noronha-Hostler published a paper on the possibility of a deformed 208^Pb nucleus. Most people assume lead 208 is spherical because it has double magic numbers but there is an unresolved puzzle in ultra-central heavy-ion collisions that a pear shape lead nucleus may resolve. However, from our study we find that it does not capture the correct fluctuations of the nucleus. This was accepted for publication in Phy Rev. C