Theory and Phenomenology within and beyond the Standard Model

Over the next decade, experiments at the Large Hadron Collider will have a very major impact on particle physics. They will confirm or disprove the Higgs field as the underlying mechanism for the generation of mass and it is to be expected that there will be signatures of physics 'Beyond the Standard Model' of particle physics. The Standard Model has been remarkably (and frustratingly) successful and yet leaves many fundamental questions unanswered. This proposal is to support the research of the theoretical particle physicists at the University of Southampton. The main goal is to provide the theoretical ideas and techniques which will help our experimental colleagues discover the Higgs Boson and signatures of new physics, to influence the analyses which will be performed and to contribute to the theoretical interpretation of the experimental data. There are many aspects to this work and we now briefly review some of these and explain the Southampton group's role. The experimental discovery signatures of the Higgs Boson, and indeed of the particles present in theories beyond the standard model, depend on the masses of these particles and on the new theories. In Southampton 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 at the Rutherford-Appleton Laboratory (RAL) inparticular) and will work closely with them in their analyses.Indeed, together with RAL, we have founded the NExT (New Experimental Theoretical Interactions) Institute with the close collaboration of theorists and experimenters as its main goal. 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. It is likely that some (or perhaps all) 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. An important aspect of standard model physics is to understand the phases of QCD at finite temperature and density; conditions present just after the big bang or in neutron stars and which are being recreated at experiments at the RHIC accelerator in the USA and at the LHC. An important objective of our research is to interpret the experimental ideas in terms of QCD, and in turn to use the results to understand the theory,