|When four force carriers directly interact, they can be used as a powerful probe for new physics.|
The Standard Model predicts a distinct behavior between force carrying particles when they directly interact with each other, so studying what happens when four force carriers simultaneously interact is a powerful test of the theory. By looking for a deviation from the predicted behavior, physicists can perform a generalized search for new physics without necessarily knowing what could be hiding in nature. The behavior of these interactions might differ from the Standard Model prediction if, for instance, there are extra dimensions of space or undiscovered, heavy particles that interact with the known force carriers. This powerful probe can be sensitive to particles that are much more massive than what can be directly produced in current particle accelerator collisions.
One four-boson interaction predicted by the Standard Model to contribute to W boson pair production is the simultaneous interaction of two photons, the carriers of the electromagnetic force, and two W bosons, the massive, charged carriers of the weak force. A recent analysis at DZero examined the contribution of this interaction in the production of W boson pairs, which is predicted to be very small in the Standard Model. The analysis focused on events where each W boson decayed into an electron and a neutrino. The two neutrinos will not interact with the detector and are only noticed by the total imbalance of energy they leave behind, so the precise measurement of each electron is important to the analysis. The analyzers built a special discriminant to characterize each event and search for any anomalies in the behavior of the four-boson interaction.
After examining all of the DZero Run II data, the analyzers found that the Standard Model predictions are accurate for the simultaneous interaction of two photons and two W bosons. Their results set limits on the size of possible deviations from the Standard Model that are between 5 and 10 times better than the best previously published limits. The result from this powerful probe of force carrier interactions provides improved constraints for many new theories of physics beyond the Standard Model.
|These physicists made major contributions to this analysis.|