I am an experimental particle physicist, with interests in top-quark physics, weak interactions, and the Higgs boson. I've done research in particle physics for more than thirty years, ever since I was a college student, and it's an honor to be able to work in a field with such grand questions and international scale. The Large Hadron Collider (LHC) at CERN in Geneva, Switzerland started operations in 2009, colliding protons at energies a factor of 3.5 higher than we've ever achieved previously with a particle accelerator. I and other physicists at the University of Nebraska-Lincoln work on the Compact Muon Solenoid (CMS) at the LHC. In 2012, we observed a new particle, which as far as we can tell is the long-awaited Higgs boson, the last missing particle of the standard model of particle physics. As a field, we spent fifty years looking for it! My own recent contribution to our knowledge about the Higgs is a search for anomalous production of this particle in association with a single top quark.  The Higgs discovery is great news, but we also expected to see other new particles by now, and we haven't. That's a problem for a lot of proposed models of particle interactions.  The LHC is currently in "Run 3" of operations, which will end in 2026, yielding our largest dataset ever.  After that we will be completing major upgrades to both the accelerator and the detector.

Data analysis is the very last step for making a physics measurement.  First we have to build and then operate the experiment.  Operations is a huge task -- there is a scientific instrument the size of a building to maintain and run, and data to process.  I am Deputy Manager of the U.S. CMS Operations Program, which is responsible for the U.S. contributions to the operation of CMS.  In my role, I am the Principal Investigator for the National Science Foundation award that paritally funds the program.  I help oversee the $35M annual budget that funds activities at 45 institutions, and work with other managers and our funding agencies (the Department of Energy and National Science Foundation) to support the work of U.S. physicists on CMS.

Besides the physics of the experiment, I'm also involved in computing issues. CMS produces petabytes of data each year, and it has to be processed, stored, transferred and analyzed. It's a huge computing task, and much of it gets done using facilities here in the United States. In 2015-19, I served as manager of software and computing for the U.S. CMS Operations Program, with responsibility for the $16M annual budget for U.S. CMS computing facilities and support personnel. At Nebraska, we host a so-called "Tier-2" computing center for CMS, where we host data that collaborators from all over the world analyze, and also run the simulations that help us understand what new phenomena might look like. I interact closely with our colleagues at the Holland Computing Center who look after the day-to-day operations of the computers. There are six other sites like ours in the U.S. (at Caltech, Florida, MIT, Purdue, UC San Diego and Wisconsin), and about fifty of them around the world. I spent nearly a decade as the leader of the team that runs the U.S. sites, and I continue to be a co-coordinator of the world-wide program. From this computing work, I've branched out into some other interesting problems in data-intensive high-throughput computing, such as the NSF-funded "Any Data, Anytime, Anywhere" project that made data access over the wide-area network transparent and reliable for users, the DIANA-HEP project that developed innovative software for large-scale data analysis, and the IRIS-HEP software institute that is enabling computational and data science research for the High Luminosity LHC that will begin operations in 2029 (we hope).  Currently we're playing around with developing computing facilities that can handle new paradigms for particle physics data analysis, and that's been fun.

I've also developed a sideline looking at the impacts of particle physics on climate change.  This grew out of my role in the last "Snowmass" community summer study, where I co-led a topical group on the social and environmental impacts of particle physics, and was an editor of a white paper on the impacts of particle physics on the earth's climate.  We got a nice writeup about this in symmetry magazine.  More recently I co-authored a paper for Annual Reviews of Nuclear and Particle Science on the sustainability and carbon impacts of potential future accelerator projects.  I have a seminar/colloquium talk on that if you are interested.