Computing matters at CMS

Lothar Bauerdick
Oliver Gutsche
Burt Holzman

Lothar Bauerdick, Oliver Gutsche and Burt Holzman, members of the CMS group at Fermilab, wrote this column.

On Monday, the LHC ended its collisions of protons on protons for 2012 and is not scheduled to resume running until 2015 when the long shutdown for energy upgrades is complete. The completion of proton collisions this week marks the end of an era for the LHC, one during which the world got its initial peek at a new energy scale, even though the collider ran at reduced energy. In this relatively short three-year run, the LHC was able to gather a sufficiently sizable data set to observe what looks like the Higgs boson and make a broad range of interesting physics measurements. CMS has published more than 200 refereed physics publications to date on this data set and will continue to mine this data for the coming years while it repairs and upgrades its detectors.

Collecting the data is just the first step in the process of physics publications. That data has to then be reconstructed, calibrated and put into a form that is useful for the 2000-plus collaborators to perform physics analysis. Furthermore, a parallel simulation effort must also be coordinated and executed in order to get the physics out. The scale of computing at CMS is something that particle physics has never seen before, using hundreds of thousands of processors located at Fermilab and around the world.

All of the CMS computing professionals at Fermilab’s Scientific Computing Division have had a significant impact on the success of CMS. These professionals operate the CMS Tier-1 at Fermilab, the largest computing facility for CMS outside of CERN, as well as the LHC Physics Center, a highly regarded resource for analysis.

You often hear in the corridors of physics departments that if you’re under pressure and need to get your analysis done quickly and reliably, one of the best places to get the job done is the CMS analysis farm at Fermilab.

Although mostly working in the background, the entire collaboration knows and appreciates the effort undertaken by the facility and operations teams, maintaining the computing centers in FCC and GCC and manning the Remote Operations Center on Wilson Hall’s first floor. With quiet efficiency, these teams have made Fermilab what it is today for CMS, a beacon of excellence in computing reliability and service. In the last quarter, the facility did not experience a single unscheduled downtime – demonstrating the commitment of the team to keeping this facility available for scientists worldwide to use.

With the most successful year yet for CMS winding down, the work doesn’t stop. While the physicists enjoy their well-deserved rest and recharge their batteries for an equally promising 2013, the computers will dutifully process data, analyze results and prepare for the higher-energy run to start in 2015, all under the watchful eyes of the CMS computing team at Fermilab.