CDF’s brightly lit offices

CDF’s full dataset consists of information from 10 inverse femtobarns.

In 2003, Higgs boson searches at the Tevatron were merely sparks in the eyes of physicists at CDF and DZero. After two years of slow running, the Tevatron had delivered a dataset only half as large as the previous Tevatron run in the 1990s. The earlier dataset yielded the discovery of the top quark.

While the data collected by 2003 produced one million W bosons, if the Higgs boson really exists as predicted, only about two Higgs bosons would have been produced by 2003 in each experiment. Even if these events passed selection criteria, they would be too hard to distinguish from other physics processes that mimic the Higgs signature. Much more data would be necessary to give the experiments a shot at discovering or excluding this amazing particle. Its existence would explain how the fundamental particles (for instance, electrons and quarks) of the universe acquire mass. For many, the outlook was bleak.

But a torch of hope was lit. Someday, the CDF and DZero collaborations would have 10 inverse femtobarns of data with which to find their Higgs boson. A femto is a small fraction, and a barn is a measure of area. An inverse femtobarn is the number of collisions happening in a very small area, in the center of the CDF and DZero detectors. With 10 inverse femtobarns, CDF and DZero would together have about one thousand Higgs bosons for their most sensitive analyses – that is, if the Higgs boson really exists.

This torch, which appeared dim at first, began to glow brightly over the years. It kept many sleepless graduate students and post-doctoral researchers awake at night, preparing never before used analysis techniques to extract the Higgs boson signal from their data.

The Tevatron delivered. In a heroic effort of ingenuity, the men and women of the accelerator division delivered almost 12 inverse femtobarns to CDF and DZero. The CDF detector was fully functional and its data acquisition systems kept up with about 10.1 of the femtobarns. CDF collaborators have sorted through this data methodically. CDF reports its first Higgs analysis of a full 10 inverse femtobarns of carefully selected data, in a search for the Higgs boson decay to two very energetic photons. In the coming months, the full dataset will be added to the dozen independent analyses that comprise CDF’s search for the Higgs boson. Analysis efforts are as strong as ever, and the sensitivity for the Higgs boson is expected to improve as much from the new data as it will from better analysis technique. CDF students and post-doctoral researchers are fighting to get that last improvement in to their Higgs analysis, demanding that no Higgs event get left in the dark. Their feverish efforts are now brightly lit by the torch of 10 inverse femtobarns of luminosity.

We wish to thank the Accelerator Division for providing 10 inverse femtobarns of luminosity!