About
I am an experimental high-energy physicist on the Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider. My research focuses on three interlocking thrusts: Higgs-boson physics through vector boson scattering, searches for physics beyond the Standard Model via long-lived particles, and the design, construction, and physics performance of the CMS High Granularity Calorimeter (HGCAL) for the High-Luminosity LHC.
I joined the FSU Department of Physics as Assistant Professor in 2016 and was promoted to Associate Professor with tenure in 2022. Before FSU I was a postdoctoral researcher at the University of Maryland (2011–2016) and completed my Ph.D. in 2011 at the University of Notre Dame with Prof. Colin Jessop, working on the first single-photon cross-section measurement with CMS and on commissioning of the CMS electromagnetic calorimeter.
Research
Higgs-boson physics with vector boson scattering
I lead the FSU contribution to the CMS measurement of the VVHH quartic gauge–Higgs coupling through vector boson scattering. The first result of that program, CMS HIG-24-003 (arXiv:2604.24531, submitted to Physical Review Letters), constrains the coupling using the full Run 2 dataset and three hadronic final states developed at FSU. A follow-up analysis incorporating Run 3 data and additional channels is now the headline going-forward project of my group.
High Granularity Calorimeter for the HL-LHC
I serve as the international Level-2 coordinator of the CMS HGCAL SiPM-on-tile project — the rear hadronic compartment of the new endcap calorimeter — and as Level-3 manager of the USCMS Phase II Endcap Calorimeter scintillator section, an $11.7M scope distributed across six U.S. institutions (FSU, Maryland, Notre Dame, Northern Illinois, Minnesota, and Fermilab). At FSU we design, fabricate, and qualify approximately 1100 motherboards and 850 back-hadronic wingboards for the readout chain; the roughly 3000 cable assemblies that interconnect them are fabricated to our designs at the University of Notre Dame. Production is now well underway.
Searches for long-lived particles
I led the CMS displaced-jet search program at √s = 13 TeV during the first half of LHC Run 2. The culminating result of that effort was the CMS search for long-lived particles produced in association with a Z boson, in which the Z tag provides a trigger handle that inclusive displaced-jet searches lack. I continue to serve the CMS LLP program as a member of the Analysis Review Committee for the search EXO-24-003 (2025).
Selected publications
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Search for vector-boson scattering production of two Higgs bosons in pp collisions at √s = 13 TeV.
CMS Collaboration, CMS-PAS-HIG-24-003 (2026); submitted to Phys. Rev. Lett. · arXiv:2604.24531 -
Search for long-lived particles produced in association with a Z boson in pp collisions at √s = 13 TeV.
CMS Collaboration, JHEP 03 (2022) 160 · arXiv:2110.13218 -
Using graph neural networks to reconstruct charged pion showers in the CMS High Granularity Calorimeter.
CMS Collaboration, JINST 19 (2024) P11025 · arXiv:2406.11937 -
Timing performance of the CMS High Granularity Calorimeter prototype.
CMS Collaboration, JINST 19 (2024) P04015 · arXiv:2312.14622 -
The DAQ system of the 12,000 channel CMS High Granularity Calorimeter prototype.
CMS Collaboration, JINST 16 (2021) T04001 · arXiv:2012.03876
Group
Current members
- Maria Mazza — postdoctoral researcher (2024–present). CMS VBS Higgs analysis; motherboard QC for HGCAL at FSU.
- Pak Yi Li — Ph.D. candidate. CMS VBS Higgs measurement in the partially boosted, partially resolved hadronic final state with missing transverse energy.
- Undergraduate researchers: Jose Stadthagen, Ben Winkler, Liam Norman, Ireland Johnson, contributing to HGCAL motherboard and wingboard quality control at FSU.
Past members
- Oleksandr Viazlo — postdoctoral researcher, 2020–2022; now Senior ML Compiler Engineer at Axelera AI.
- Suho Kim — Ph.D., 2022. Thesis on machine-learning-based searches for long-lived scalars in CMS. Now in industry in South Korea.
- Daniel Diaz — Ph.D., December 2020; postdoctoral researcher at UC San Diego (2020–2025); now Computational Research Scientist at UC San Diego.
Interested in joining the group? See contact below.
Teaching
I regularly teach the two upper-division laboratory courses in the FSU Physics major:
- PHY 3802L — Intermediate Laboratory (junior level).
- PHY 4822L — Advanced Laboratory (senior level).
I introduced oral interview assessments in both courses to give students practice with scientific oral defense and to evaluate the use of AI tools in lab work. In Fall 2024 I delivered a guest lecture series, High Energy Physics: Detectors Past, Present, and Future, at the CMS LHC Physics Center at Fermilab — archived on YouTube.
Contact
Email: tkolberg@hep.fsu.edu
Office: Department of Physics, Florida State University
77 Chieftain Way, Tallahassee, FL 32306