Physics Theory Consolidated Grant

Experiments at the Large Hadron Collider (LHC) have been accumulating huge amounts of data, and famously have announced the discovery of a Higgs-like particle. Over the next decade the LHC will have a very major impact on particle physics. It will further establish, or rule out, that the new particle is the Standard Model Higgs, and in turn whether this provides the underlying mechanism for the generation of mass. It is to be expected that there will be signatures of physics Beyond the Standard Model. The first and so far only evidence for new physics Beyond the Standard Model is neutrino mass and mixing which may shed light on the unanswered well known puzzles such as the pattern of fermion (including neutrino) masses and mixing angles and the strength of the four forces. Also, neutrino physics may shed light on the abundance of matter over anti-matter in the universe via leptogenesis and the presence of dark matter and magnitude of dark energy (as deduced from many observations). The forthcoming neutrino experiments and cosmological observations will shed further light on these questions. Finally gravity and quantum mechanics fail to be combined within this framework. This proposal is to support our theoretical work at the University of Southampton which addresses these questions, and help our experimental colleagues discover signatures of new physics, and interpret the new data. We have expertise and experience in devising strategies for these searches and also in developing theories of new physics. We have close links to the UK experimenters working at the LHC and will work closely with them in their analyses. Indeed, together with the Rutherford-Appleton Laboratory (RAL), we have founded the NExT (New Experimental Theoretical) Institute with the close collaboration of theorists and experimenters as its main goal. It has expanded over the years to also include Sussex, RHUL and (more recently) QMUL. Meanwhile we have developed a web-interface (HEPMDB) which allows researchers to test their favourite model using supercomputers without needing to be experts in computer algebra and supercomputing. The results from the analyses in turn will constrain the new theories, for example by confirming or disproving the idea of supersymmetry, and guide us in unravelling the next level of fundamental physics. These are remarkably exciting times! Of course, in order to be confident that we have observed a signal of new physics we have to be sure that what we are seeing is not simply a subtle effect of the standard model. Frequently, as a result of our limited ability to quantify the effects of the strong nuclear force, this is difficult to do. In Southampton we have outstanding expertise in quantum chromodynamics, QCD, the theory of these strong interactions. This includes a major research programme using state-of-the-art supercomputers to compute these effects for a wide variety of physical processes. A major component of our future programme is to expand and develop the activity of numerical simulations on the IBM BlueGene/Q supercomputers. It is likely that some new particles will be too heavy to be observed directly at the LHC. In that case their presence will have to be deduced indirectly, by observing deviations from Standard Model predictions for rare processes. The programme of numerical simulations will be central in establishing these deviations as will the analytical techniques which we are using. Finally, we develop new ways of predicting the behaviour of strongly interacting systems which informs physics beyond the standard model, cosmology, the quantum mechanical description of gravity, and even condensed matter physics. One of these approaches is dubbed holography and is deeply connected to theories of gravitation by providing an alternative description of strong coupling in terms of General Relativity, String Theory and Black Hole physics.