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July 9, 2014

Reinhard Schwienhorst: Collaboration, Competition and Collisions

July 9, 2014

Reinhard Schwienhorst is an associate professor of physics and astronomy. He is a particle physicist, exploring the energy frontier, studying the laws of nature at the highest energies together with his MSU colleagues and collaborators from around the world on the ATLAS experiment at CERN near Geneva, Switzerland.

As a German-American who works at MSU on an experiment located in Switzerland and France, I have always been attracted to the globe-spanning internationality of particle physics. I am part of the MSU team in the ATLAS experiment at the Large Hadron Collider at CERN, where the Higgs boson was discovered recently.

I have colleagues on every continent, and I have worked with students and postdoctoral researchers from countries from Germany to China. When I go to the cafeteria at CERN for lunch, I hear a different language spoken at every table, yet everyone works together to build detectors, run experiments and analyze data.

At the same time, it's not all Kumbaya. We organize ourselves into independent collaborations and experiments that compete with and cross check each other. Each accelerator typically has at least two experiments that both record collisions.

At the LHC, there is not only our ATLAS experiment. There is also a second experiment, CMS that directly competes with us. They also record proton-proton interactions, and their physics goals are the same as ours. We try to beat them and they try to beat us. We all record collisions of LHC beams, so the inputs to our measurements are the same.

But it's up to each individual experiment to push measurements in different directions. We compete in analyzing data as quickly as possible and in understanding the collision data as precisely as possible. We also compete for the attention and interest of our theory colleagues.

MSU was in the middle of this competition a few years ago when the Tevatron collider at Fermilab near Chicago was the world's leading particle physics machine. MSU researchers were on both of the competing experiments at the Tevatron.

In 2009, I was leading a group on the D0 experiment that was close to breakthrough measurement. I had to keep my office door at MSU shut for phone conversations and meetings because I had to make sure that my CDF experiment competitors would not spy in on me. It was especially awkward and stressful because one of the leaders of the CDF analysis was Kirsten Tollefson, whose office is just two doors down the hall from mine and who is my friend outside of work.

But lucky for me and for our friendships, we survived those stressful times. The Tevatron experiments are now finalizing the last publications based on the data taken until 2011. And we are now combining our results from the two Tevatron experiments. In fact, earlier this year we published the first observation of a process that was only observable by combining the two experiments.

Each individual experiment did not have enough sensitivity, and only by working together could we measure this process. Shortly after publishing the first observation, we published another combination, this one combining not only the two Tevatron experiments but also including the two LHC experiments.

Everyone in the MSU particle physics group, faculty, postdocs, students, engineers and technicians contributed to that paper, and most of us as members of more than one experiment. It was the first worldwide-combination effort, and I am proud to have been a part of it.