Mike Cooke

The combined Tevatron experiments test whether the Higgs boson follows the intricate blueprints of the Standard Model. The Standard Model dictates the intricate relationships between the particles it describes, but does the Higgs boson follow that blueprint and fit those specifications? If so, the Higgs boson must have the predicted properties, including the correct production rate and the right preferences for decaying into other particles. The Tevatron experiments, CDF and DZero, have just released the results of their combined study…

Getting four of a kind is rare and exciting when playing poker and when examining events from DZero. While being dealt four of a kind in poker is much more rare and memorable than getting two pairs, finding either is exciting in an event at DZero. The neutral Z boson, a weak force carrier, can decay into a pair of leptons, such as electrons or muons. This kind of decay is frequent enough that researchers use Z boson events to…

With all analysis channels updated to use the full Tevatron Run II data set, DZero enhances the picture of the newly observed Higgs-like particle and tests its consistency with the Standard Model. Determining whether the new particle observed last year is the Standard Model Higgs boson requires a look at the big picture. The Higgs boson plays an important role in the Standard Model, giving mass to quarks, charged leptons and the weak force carriers, but it is not the…

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…

The Higgs boson does not directly interact with photons, but creates pairs of them through loops of other particles—perhaps including particles that have yet to be observed. In the Standard Model, the Higgs boson interacts with other particles in proportion to their mass, yet its decay into pairs of massless photons is one of the most interesting and important channels to study. Not only was this one of the main discovery channels for the Higgs boson candidate observed last July,…

Models of strong force interactions must use input from experiments to improve their predictions of the size and shape of important processes. To estimate a signal or background process at a particle collider, two seemingly simple questions must be answered: “How much of it is there?” and “Where will it appear in the detector?” Knowing the rate and shape of each process is necessary to build an analysis that can reject backgrounds while keeping and measuring the signal. But interactions…

Editor’s note: Starting this year, Fermilab Today will bring you more results from research at the Energy, Intensity and Cosmic Frontiers. We will publish these results on Thursdays and Fridays, highlighting the full breadth of Fermilab’s experiments. Measuring how often a W boson and a bottom quark are produced together provides important constraints on models of the strong force. Studies of the newly observed Higgs-like boson, measurements of the top quark and many searches for exotic physics cannot happen without…

The rare decay of a Bs0 meson into two muons would be greatly enhanced by some models of new physics. While the Standard Model allows the Bs0 meson, the particle containing a strange quark and an antibottom quark, to decay into two muons, the chance of that happening is about half that of a given lottery ticket winning the Mega Millions jackpot. This rare process is more common in theories with new physics, such as supersymmetry, where the presence of…

The latest combined results from CDF and DZero test whether the newly observed particle measures up to the expectations of a Standard Model Higgs boson. If the new particle discovered in July is the long-sought Higgs boson, then it should measure up like one when compared to the predictions of the Standard Model. The Higgs boson plays an important role in the Standard Model, giving mass to the quarks, charged leptons and weak-force carriers, but the Standard Model version of…

Events containing a charm quark and a photon allow physicists to shed light on the behavior of the strong force. When DZero physicists scrutinize events in their data that contain a charm quark and a photon, they can shed light on the behavior of the strong force. In the Standard Model, it is difficult to accurately predict quark production because of the complex strong force interactions involved. Instead, theorists build models of the strong force that must be constrained by…