Probing the Standard Model

Effective field theory provides a crucial tool both for probing the electroweak standard model and for understanding QCD. For example, it allows a clean separation between QCD and electroweak physics in the description of B meson decays. This means that some processes, in which the electroweak physics is understood, can be used to study hadron structure, whereas other processes, in which the QCD physics is understood, can be used to look for deviations from the standard model, such as in its description of CP violation. Iain Stewart is working on applications of effective field theories, and recently has developed a framework that extends this formalism to processes with energetic hadrons. For weak B meson decays this provides a new approach to understanding QCD effects which were previously thought to be intractable or model-dependent.

MIT also has a strong experimental B-physics program led by Christoph Paus on CDF and Gabriella Sciolla, Frank Taylor, and Richard Yamamoto on BaBar.

Electroweak probes of nuclei and nucleons have been an ongoing focus of William Donnelly and collaborators.

Edward Farhi and Robert Jaffe have been studying what becomes of fermions in the Standard Model when they become very massive. Little is known about this fermion "decoupling", and it is possible that they are replaced by lower mass solitons stabilized by quantum fluctuations.

Postdocs and visitors working in this area include Bjorn Lange.

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