Caroline Kathrin Riedl

Caroline Kathrin Riedl
Caroline Kathrin Riedl she/her/hers

Primary Research Area

  • Nuclear Physics
Associate Research Professor
467 Loomis Laboratory


We are awaiting first beams for the sPHENIX experiment at BNL in early 2023. Since 2021, I have been co-chairing the sPHENIX commissioning task force. After my return to UIUC from CERN in mid-2018, I was in charge of the scientific supervision of the sPHENIX EMCal block project at the Nuclear Physics Lab (NPL). Our group completed the production of more than 5,000 absorber blocks for the sPHENIX electromagnetic calorimeter in the end of 2021, which was only possible because we had more than six dozen undergraduate students and technician helpers working with us. Each block consists of an array of 2,668 manually assembled scintillating fibers in a tungsten-epoxy matrix and was constructed from scratch by our NPL technicians and student workers. The EMCal blocks were shipped to BNL, where they are assembled to sectors. The EMCal sectors will be installed in sPHENIX in summer 2022. For COMPASS, a nuclear-physics experiment at CERN, we are currently wrapping up the analysis of the spin-dependent Drell-Yan data. I have been serving as a member of the COMPASS publication committee since 2018.

I joined the Department of Physics at the University of Illinois as Research Assistant Professor in 2013. In 2013-2015, I was the project coordinator for a detector upgrade for COMPASS at CERN (Geneva, Switzerland / Prevessin, France). I organized the prototyping, construction and assembly of a large-area planar drift chamber (DC5). The DC5 detector was constructed in the US, mostly at the Nuclear Physics Laboratory. This would not have been possible without a small army of undergraduate students. The detector parts were shipped to CERN in fall 2014 and assembled. DC5 was installed into COMPASS in May 2015 and has been successfully collecting valuable data since then in two Drell-Yan runs 2015 and 2018 and two GPD runs in 2016/17. In 2018, I served as the COMPASS technical coordinator. From 2016 through 2019, I was able to secure grants for COMPASS data productions on NCSA's supercomputer Blue Waters. Our team used more than 13 million Blue-Waters node hours to produce COMPASS data for high-level physics analysis, for the study of high-precision detector efficiencies and for detailed Monte-Carlo simulations. We continued COMPASS data productions in 2020 and 2021 on the next-generation NSF-funded supercomputer Frontera at TACC.

After my PhD on HERMES data, a fellowship with INFN Frascati (Italy) and a postdoc association with DESY allowed me to continue my research at DESY. I participated in the commissioning and operation of the HERMES recoil detector and lead the analysis and publication of hard-exclusive data collected with this detector. From 2008 to 2010, I was the deputy analysis coordinator of HERMES and from 2007 through 2012 the DVCS and exclusive physics convener. In 2011 and 2012, I worked from DESY as main data quality manager for CMS, one of the LHC experiments at CERN, and contributed to the analysis of the Higgs-boson decay into two tau-leptons and successively into muons.

I received my diploma degree in physics from the University of Erlangen-Nuremberg, Germany, in 2001. My diploma thesis was on (1+1)-dimensional quantum field theoretical models and massless mesons in dense nuclear matter at zero temperature. From 2002 on, I focussed my research on experimental particle physics and worked at DESY (Hamburg, Germany) on data from the HERMES experiment. I investigated the tensor structure of polarized deuterons in deep-inelastic electron-deuteron scattering and received my PhD with the University of Erlangen-Nuremberg in 2005.

Academic Positions

  • Associate Research Professor, University of Illinois at Urbana-Champaign. Nuclear Physics. Since 2021
  • Research Assistant Professor, University of Illinois at Urbana-Champaign. Nuclear Physics. 2013 - 2021.
  • Research Associate (Postdoc), DESY-Zeuthen, Germany. Particle Physics. 2006 - 2012.
  • Research Associate (Fellow), INFN Fracsati, Italy. Particle Physics. 2005 - 2006.
  • Graduate student / teaching assistant, University of Erlangen-Nuremberg, Germany. 2002 - 2005.


Other Instructional Activities

  • 497 independent study sping 2022
  • 497 independent study spring 2021
  • 403 instructor in fall 2013

Research Statement

I am interested in the structure of nucleons and nuclei. Modern approaches to investigate nuclear structure involve transverse momentum dependent parton distribution functions (TMDs) and generalized parton distributions (GPDs). COMPASS at CERN collected TMD-related data in 2015 and 2018. The analysis of part of these data hints to a sign change between the Sivers TMD measured in Drell-Yan vs. that measured in semi-inclusive deep-inelastic scattering and grad students of our group currently analyze the full data set. The future sPHENIX data collected with transversely polarized proton beams will also allow for TMD-related studies. We will analyze these data while preparing the advent of the Electron Ion Collider, the future polarized electron-proton collider at BNL to start after 2030.

Some of my recent talks:

Research Interests

  • Experimental nuclear physics: spin structure of the nucleon in Drell-Yan, semi-inclusive deep-inelastic scattering (SIDIS) and hard exclusive processes using polarized nuclear targets and hadron or lepton beams
  • Transverse-momentum dependent (TMD) degrees of freedom in the hadron
  • Development and construction of detectors for nuclear-physics research.

Selected Articles in Journals

Articles in Conference Proceedings