TH seminar - Gravitational corrections to precision observables, Christian Reuschle

Thursday 7 May 2009, 16:15 → 17:15 Europe/Brussels

The theory of gravity distinguishes it self from the theories of the other three known forces in the sense, that it shows it self as highly non-renormalizable, when treated as a Quantum Field Theory. However, the situation might not be as bad as one thinks. In deed 30 years ago, 't Hooft and Veltman showed, that the theory of pure gravitation is one-loop renormalizable. Eight years later it was shown by Omote and Ichinose, that even the YM field interacting with fermions on a general curved space time has a one-loop counterterm that can be obtained. In my talk I will not go into the details of those calculations but rather stay much simpler and focus on how to implement the theory of gravity plus QED in a set of Feynman rules to obtain vertices and propagators, both for the massless and massive graviton case. Further we will see how to proceed with the actual one-loop calculations in this case, which do not defer that much from the calculations we are used to, in order to obtain gravitational corrections to the anomalous magnetic moment of the electron. We will see, that the UV divergencies in fact cancel and a finite answer remains.