David Sperka

David Sperka

Research Faculty (Research Assistant Professor)


Research Interests:

My research is focused on measuring the properties of the recently discovered Higgs boson and searching for new particles and phenomena with the Compact Muon Solenoid (CMS) detector at the CERN Large Hadron Collider (LHC). The LHC is the world's largest and most powerful particle accelerator, and the CMS detector is an all-purpose detector designed to detect and record high-energy particle collisions. The CMS experiment discovered the Higgs boson in 2012, the final piece of the Standard Model of particle physics, but many of its properties remain unexplained. For example, the mass of the Higgs is not protected by any symmetry from large radiative corrections in the Standard Model, and therefore it is not understood why its mass is near 125 GeV. Furthermore, the coupling strengths of the Higgs to fermions are free parameters that are not predicted by the theory. I perform global fits of all available Higgs boson measurements to extract these coupling strengths and compare them to the Standard Model predictions. I am also searching for exotic Higgs decays that are predicted by beyond the Standard Model (BSM) theories.

In addition, many BSM theories predict the existence of new particles that can be produced at the LHC and I am searching for these new particles. In particular I am looking for a particle known as a Z' boson that can have a mass below the electroweak scale. If such a particle exists, it may help explain several anomalous measurements in particle physics. These anomalies include the tension in the measurement of the anomalous magnetic moment of the muon, the gamma ray excess observed in the galactic center, and the lack of a dark matter signal at direct detection experiments. I am also interested in searching for additional Higgs bosons that are predicted by BSM theories such as Supersymmetry.

I am also involved in the design and operation of the Trigger and Data Acquisition system of CMS. I am working to utilize advanced techniques to extract more or better data from the CMS detector. These techniques include accelerator platforms based on GPUs and FPGAs, as well as the use of modern machine learning algorithms. These studies are aimed towards future data taking periods of the LHC that will produce a dataset more than 300 times larger than the one used to discover the Higgs boson.

Selected Publications:

“Observation of tt̄H production”, The CMS Collaboration, Phys. Rev. Lett 120 (2018) 231801 (Editor’s Suggestion)

“Measurements of properties of the Higgs boson decaying into the four-lepton final state in pp collisions at √s = 13 TeV, The CMS Collaboration”, J. High Energ. Phys. 11 (2017) 047

“The CMS trigger system”, The CMS Collaboration, Journal of Instrumentation 12 (2017) P01020

“Measurement of differential and integrated fiducial cross sections for Higgs boson production in the four-lepton decay channel in pp collisions at √s = 7 and 8 TeV”, The CMS Collaboration, J. High Energ. Phys. 04 (2016) 005

“Search for W' to tb decays in the lepton+jets final state in pp collisions at √s = 8 TeV”, The CMS Collaboration, J. High Energ. Phys. 05 (2014) 108

For a full list of publications, please see the attached CV.