New Frontiers in Particle Physics, Cosmology and Gravity

Particle physics is the study of the fundamental building blocks of nature, how they interact and how they lead to what we observe from the smallest scales to the largest. The Standard Model (SM), which is built on quantum field theory (QFT), is an impressively accurate description of all data to date, from colliders to astronomical observations. Nevertheless, there are many aspects we do not understand from the pattern of particle masses to our lack of a quantum theory of gravity.

The Large Hadron Collider (LHC) will accumulate ever-increasing amounts of data over the next decade; it famously discovered the Higgs particle in 2012 and could possibly discover new physics beyond the SM. So far the only experimental evidence for such new physics is neutrino mass & mixing, which may yet shed light on the pattern of particle masses, strength of the four forces, and observations of abundance of matter over anti-matter in the universe, dark matter and dark energy. Upcoming experiments will address these questions. We have close links to the LHC through the NExT institute and will help experimenters discover new physics, by devising strategies for searches and interpreting the data, for example through our easy-to-use interface (HEPMDB) to supercomputers and the definition of new triggers (to be implemented in the current LHC upgrade) for physics previously overlooked. A common thread is the violation of the combination of charge conjugation symmetry (C) and parity (P), which may be observed soon in new sectors leading to major breakthroughs. In order to be sure that we have found new physics we must exclude subtle effects from the SM, or deduce it indirectly from small deviations from the SM. The strong nuclear force (QCD) can make this difficult, but we have outstanding expertise in computing these effects using state-of-the-art supercomputers and have now reached a level of precision where we must include effects of electromagnetism (QED) and differences in the masses of the quarks.

It is important to continue to develop QFT, e.g. new tightly constrained theories have been found that become massless, at long or short distances. We use these to make better predictions of particle scattering and to better understand theories when mass is re-introduced or to work towards quantum gravity. The notion of "holography" has linked apparently very different systems such as QCD and Black Holes. We are developing it to learn more about a quantum gravity, and use gravity to study QCD including in extreme environments such as the cores of neutron stars. We are extending lattice field theory simulations to study gravity and cosmology (early-universe physics), including testing holographic models.

Who are likely to be interested in or will benefit from this research (directly or indirectly)?

1) Intel and other High Performance Computing manufacturers
2) Leading IT companies (e.g. IBM, Microsoft)
3) The commercial sector
4) Other areas of science (e.g. Biology, Medicine, Chemistry)
5) Schools
6) The wider public
7) Policy makers

How will they benefit from this research?

1) Our work in lattice QCD has a significant scientific pull on the development of massively parallel supercomputers; most recently Intel supported UKQCD, of which we are a founding member, through the Intel Parallel Computing Centre in Edinburgh for algorithm and software development. Our work is recognised as driving the development of high performance computing more generally.
2) Our development of the HEPMDB web-interface to High Performance Clusters and potentially cloud computing allows people to take advantage of cluster computing without learning advanced computing methods for data processing. This is likely to be of interest to leading IT companies.
3) The developments in (1) and (2) could be of interest to the commercial sector that use High Performance Computing (e.g. autonomous cars, AI/ML more generally, weather forecasting, drug development, advanced engineering design, film and games industry, high finance etc). Half our PhD students leave to pursue careers outside academia, where the high-level analytical, computational and mathematical skills they have developed prove to be valuable. Since many settle in the UK this is a direct benefit to the economic competitiveness of the UK.
4) The developments in (1) and (2) will be of potential benefit to other areas of science that themselves have an impact (e.g. Medicine to Health).
5) The UK is currently not producing enough maths, physics and engineering graduates to meet demands from all sectors. Our public engagement programme includes particle physics masterclasses and interactive shows within schools, and aims to encourage more pupils to study physics in sixth form and at university. We are particularly targeting women and BME students, who are currently under-represented in physics.
6) Our research communicated through a very strong and active outreach programme has a strong benefit to culture of the nation. It would be fair to say that everybody has heard of the LHC, and the famous discovery of a Higgs-like particle, and many ask with enthusiasm for news updates. There is a strong sense of ownership and pride in the wider public over this endeavour. Further, the fact that we have written four books in the last three years, targeting audiences at various levels and propagating our science to UK and worldwide Universities, research labs, libraries, etc. is factual evidence of our ability to reach out above and beyond our strict research communities.
7) Our group provides timely, independent and authoritative advice to national and international decision makers including, for example, the EC (through executive panel membership), the UK (through participation in REF2021 units) and Belgian (through the Belgian research council FWO) goverments.

Importance and timescales?

It is widely recognised that it is of crucial importance that the UK position itself strongly in the high-added-value technologically advanced areas of the economy. The contributions described in (1) to (4) all work towards this. As stated above our work on Lattice QCD is recognised as driving the development of high performance computing. The impact of our work on web-interfaces may take 5 to 10 years to realise. The highly trained PhD students that enter the market have an immediate impact and often over relatively short periods of time (10 years) climb to influential positions within their chosen sector. The UK sense of ownership and well-being flowing from the LHC research is happening now.