Community Research and Development Information Service - CORDIS

Periodic Report Summary 1 - NONPLANAR (Simplifying the non-planar sector of gauge theory.)

The main aim of this project has been to improve our ability to calculate accurately in the theories which describe nature. An important motivation for this aim for accuracy comes from the Large Hadron Collider at CERN, where experimental physicists are studying nature at unprecedented precision. It is important that our ability to make theoretical predictions should keep up with the accuracy of the data in order to allow us to confront our expections for known physics against nature; it is when theoretical expectations are seen to differ from experimental reality that we can discover new physics.

To date, most of the tools we have built to enable accurate predictions have focused on the so-called "planar" parts of theoretical calculations. In this sense, precision planar predictions is currently the state-of-the art in the field. The project focuses on corrections which are of a different type, known as "non-planar". Non-planar parts of a process are typically smaller than planar aspects; however, at the level of precision we need, they will become important. The project builds on the recent realisation that there are close links between planar and the non-planar contributions. A specific example is colour-kinematics duality. The rules of this duality allow one to set up a calculation of a physical process in such a way that information from the planar sector is automatically propagated to the non-planar sector.

The present research project provided partial funding for a small team based at the Higgs Centre in Edinburgh working on these ideas. The team consists of Doctors Donal O'Connell (holder of the CIG fellowship) and Alexander Ochirov, who was hired using fellowship funds supplemented by the University of Edinburgh. During the reporting period, the team has published seven research papers in high-impact journals. This work has had a very positive impact on the research career of the Marie Curie Fellow, Dr. O'Connell, supported by the project. His appointment at the University of Edinburgh is now permanent, and he has been promoted to the academic position of Reader. This is a particular success for the integration aspect of the fellowship.

The research work of the group has proceeded along four basic lines. Firstly, the group described a simple algebraic algorithm for determining the non-planar contributions to a particular process directly from a complete planar prediction. They also extended the concept of colour-kinematics duality, which enables the link from planar to non-planar, to include the contributions of the sub-atomic quarks. An important third line of research was not anticipated in the project proposal: the group realised that the notion of colour-kinematics duality implies a close connection between classical solutions of general relativity and classical solutions of Yang-Mills theory. Thus, colour-kinematics and the associated double-copy construction relate the Schwarzschild black hole to the familiar electromagnetic Coulomb charge. Finally, this grant also supported work of a more phenomenological characater: we studied the interplay of extensions of the standard model by singlet scalars with electroweak baryogenesis.

Reported by

United Kingdom


Life Sciences
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