Tevatron publishes evidence in search for a Higgs

The combined CDF and DZero search for the Higgs boson decaying to a pair of bottom quarks revealed evidence for a particle consistent with the Standard Model prediction.

The month of July 2012 is bound to be remembered as the crescendo of the summer of the Higgs boson. It began with the announcement of results from the Tevatron’s search for the Standard Model Higgs boson, followed immediately by reports of the observation of a new particle by the LHC experiments. As the month continued, the CDF and DZero experiments released 10 publications on Higgs searches in multiple decay channels, building the pillars of the Tevatron’s search for the Higgs boson in the state most difficult to pursue at the LHC, the Higgs boson decaying into two bottom quarks. Last week ended with the submission of the keystone paper in that combined effort, in which CDF and DZero announce finding evidence of a particle in the bottom quark pair search channel.

However, the Standard Model is not the only theory that predicts a new particle compatible with the experiments’ current observations. Now that this new particle has been found, the high-energy physics community is switching gears from conducting searches to performing measurements.

If this new particle is the Higgs boson, the Standard Model predicts its behavior with high accuracy. The Standard Model dictates how often it should be produced in particle collisions and the different rates at which it should decay into pairs of bottom quarks, photons, Z bosons and other particles. If any of these properties are found to be inconsistent with the Standard Model prediction, then this new particle may be the first indication of new physics beyond the Standard Model.

The CDF and DZero experiments are particularly sensitive to the Higgs boson’s decays to pairs of bottom quarks, the most probable decay channel of the low-mass Higgs boson, which complements the favored search channels in pairs of Z bosons or photons at the LHC. Had the Tevatron experiments’ combined search for the Standard Model Higgs boson failed to find a sign for a new particle in decays to pairs of bottom quarks, it might have indicated that the newly observed particle was not the Higgs boson predicted by the Standard Model. So far, these exciting results paint a picture consistent with the expected behavior of a Standard Model Higgs boson, but the study of its properties has only just begun.

—Mike Cooke

The CDF and DZero collaborations thank AD, PPD and CD for the important fundamental contributions they have made to our physics program. We acknowledge support from many national and international funding agencies, especially DOE and NSF.