Phenomenology from Lattice QCD and collider physics

The Glasgow theory group has a strong reputation in studies of the subatomic world, and pushing forward our understanding of how it works. This is aimed at uncovering the fundamental constituents of matter and the nature of the interactions that operate between them. There are two approaches to this, and we will use both of them. One is to perform very accurate calculations within the theoretical framework of the Standard Model that we believe correctly describes the particles that we have seen so far and the strong, weak and electromagnetic forces of Nature. Discrepancies between these accurate calculations and what is seen in experiments will then point the way to a deeper theory that describes fundamental particle physics more completely. The second method is concerned with what we might see in LHC results, now appearing, if one or other of the suggested deeper theories is correct. We must make sure that we optimise the analysis of these experiments to learn as much as possible.

Accurate calculations in the Standard Model have foundered in the past on the difficult problem of how to handle the strong force. This force is important inside particles that make up the atomic nucleus, the proton and neutron and a host of similar particles called hadrons produced in high energy collisions. The constituents of these particles are quarks, and they are trapped inside hadrons by the behaviour of the strong force. This 'confinement' of quarks makes calculations of the effect of the strong force on the physics of hadrons very challenging. It can be tackled, however, using the numerical techniques of lattice QCD. This method has been tested thoroughly by the Glasgow group in precision calculations of hadron masses and their comparison to experiment, and its current acceptance as a precision tool is based in no small part on their work. Glasgow continues to lead progress and here we propose further, harder calculations that will predict more details of how hadrons decay from one type to another via the weak force. The comparison of accurate results with experiment allows us to constrain the parameters of the weak force that allow for violations of symmetry between matter and antimatter. We plan to push down errors for these calculations and that will allow us to test the Standard Model very stringently.

The Glasgow team will also investigate theories that go beyond the Standard Model and test them with LHC data. The recent discovery of the Higgs boson is the last piece of the Standard Model and is a triumph for both theoretical and experimental particle physics. However, we must ensure that the particle discovered is indeed the Higgs boson of the Standard Model, so we must undertake a comprehensive programme to measure its properties. New physics may show up by subtly modifying these properties and we will devise ways of looking for these effects. The LHC will also produce large numbers of top quarks for the first time, and since the top quark is the heaviest particle in the Standard Model, one expects its properties also to be affected by new physics. So, as for the Higgs boson, we will also investigate top quark properties using a general model independent framework. We will then examine specific new physics models, such as theories of Grand Unification, which unify the three forces together as one single force. We will determine how these exciting and fundamental theories affect the particle properties described above and thereby confront them with LHC observations. Experimental studies on the Higgs boson and top quarks are being led by the Glasgow ATLAS group and we will coordinate with them to uncover the fundamental truths of the universe.

The next few years will be a very exciting time for theoretical particle physics and Glasgow aims to be at the forefront of this work.

The impact of our research may be split into a number of different areas. Firstly, there is the impact on other academic disciplines:

* Our results in both lattice QCD and collider physics will feed directly into experimental physics analyses, aided by direct collaboration with experimentalists where necessary. We expect significant impact in this area during the three year timescale of the grant, but our results will continue to generate such impact after this (e.g. with future LHC data).

* Dr White's work on web mixing matrices will have immediate impact in contemporary combinatorics, leading to publications in leading mathematics journals (e.g. Journal of Combinatorial Theory), and possible applications in computer science. This impact will be aided by a close collaboration with computer science colleagues at Strathclyde University.

Secondly, there is the use of our research to encourage young people to enter physics degrees, or to better equip graduates for entry into the private sector:

* We will continue to inspire young people by presenting our research results during the annual Glasgow Particle Physics Masterclass, attended by Scottish schoolchildren. Over the last four years, 500 pupils have attended, with 65% subsequently applying to study with us. Teachers report increased engagement with physics lessons, and 22 of the participants from low opportunity areas (as defined by the Scottish Index of Multiple Deprivation) have gone on to visit CERN in a programme organised by Glasgow Particle Physics.

* We will continue to engage project students at undergraduate and Masters level in our research, leading to enhanced training in computational and analytical skills, as well as academic publications (past examples include White & Oxburgh's work on BCJ duality).

Thirdly, there is the use of our research (or that of STFC in general) to foster scientific awareness amongst the public:

* We will continue to develop a relationship with colleagues at the Glasgow School of Art (aided by the Scottish Crucible programme), with a view to presenting a public art exhibition themed around STFC-related science.

* Dr Miller will continue his role on the Gifford committee, which organises prestigious lectures of joint interest to scientists and theologians.

* We will continue to engage our PhD students with outreach activities. A recent success, that they have participated in, is the exhibition to celebrate Scotland's involvement in the Large Hadron Collider at the Scottish Parliament.

Finally, there are Knowledge Exchange (KE) opportunities using methods and / or knowledge of theoretical physics in other disciplines:

* We will continue to engage with relevant interdisciplinary networks e.g. the Scottish Crucible programme, Royal Society of Edinburgh (RSE), in order to investigate possible KE opportunities. A mechanism for realising this impact will be the supervision of joint project students at undergraduate and / or Masters level (e.g. Dr White currently has two students working on applying mathematical modelling to aid public health policy).

* Prof. Davies will continue to engage with learned societies on advocacy and policy issues (previous examples include chairing the IOP Diversity Committee). She will also continue to support Women in Physics initiatives through the Scottish Universities Physics Alliance, and nationally through the IOP.