Deciphering the Higgs signature

The signature a Higgs boson event leaves in the DZero detector may not be unique to a single mode of Higgs production.

The search for the Higgs boson begins by looking for its signature, or the final decay products that are measured by the detector. Because it has many ways of being produced and decaying, Higgs boson events have numerous signatures, and a particular signature may be shared by multiple production and decay modes. After a signature is identified, it must be deciphered while considering all possible sources of signal and background. A recent result from DZero focuses on the study of one specific signature, consisting of an electron or muon, missing energy indicating a neutrino, and two or more jets of particles.

The analysis includes signals from many modes of Higgs production and decay, some of which have not been previously analyzed at the Tevatron, and updates one of the most sensitive searches for a Higgs boson decaying into two bottom quarks. To optimize the sensitivity to each source of signal, the analysis was divided into channels based on the total number of jets in the event and the number and properties of identified bottom quark jets. Special discriminants were built to separate the unique mixture of signals from the differing background contributions in each channel. In total, about 150 distinct variables were used to characterize the events across all analysis channels.

No significant excess of events was observed when considering this Higgs signature on its own, but its sensitivity will be an important contribution to the combined Higgs boson results from DZero and the Tevatron. The analysis team also presented the first results based on this signature for models where the Higgs boson disfavors decaying into quarks and leptons or has an enhanced production rate due to the existence of an undiscovered fourth generation of quarks.

The Higgs boson’s signature is not the only one noteworthy for this analysis. Two special names of undergraduates also adorn this particular paper, students who helped establish the new lepton, neutrino-plus-four-jets channel, earning them a place on the DZero author list for this result!

Mike Cooke

These physicists made major contributions to this analysis.
The DZero physics coordinators organize the collaboration’s active research topics and oversee the internal review process for all physics analyses before they are submitted for publication.