Heavy quarks

Surprisingly, when dealing with heavy quarks, some aspects of the Standard Model become simpler. Decay of these quarks are then are sometimes especially good probes of the Standard Model.

While I have a variety of contributions to this topic, there are two papers that I would like to highlight. One is my paper with Gustavo Burdman on the union of heavy quark and light quark symmetries. This describes how chiral symmetries can be manifest in a system that also has a very heavy quark.

The other paper is one on final state interactions in heavy quark decays. This is interesting partly for the topic itself, which is relevant for CP violating asymmetries, but also for its connection with standard calculations in perturbative QCD. We find that the power enhancement of Regge exchange boosts a soft contribution from being 1/m_B^2 to being of order unity. Perturbative QCD argues that this should be of order 1/m_B^2 , but misses the Regge power enhancement. It seems that perturbative treatments, including SCET, are missing the Regge physics. This remains unsettled, and I hope to have a contribution to the topic soon.

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Research and teaching pages for John Donoghue