The Lancaster, Manchester, Sheffield Consortium for Fundamental Physics: Particle Physics from colliders to the Universe

Lead Research Organisation: University of Manchester
Department Name: Physics and Astronomy

Abstract

Particle physics is all about understanding the elementary building blocks of nature and their interactions. Over the years, physicists have developed the Standard Model of particle physics, which is extremely successful in describing a very wide range of natural phenomena from things as basic as how light works and why atoms form through to the complicated workings inside stars and the synthesis of nuclei in the first few minutes after the Big Bang. However, we know that the Standard Model is not the whole story for it leaves many questions unanswered. Our proposal focuses on these unanswered questions and the way that scientists are addressing them using experiments like the Large Hadron Collider (LHC) or observations like those made using the Planck satellite.
The discovery at the LHC of a Higgs boson was a major milestone in our quest to understand the origin of mass. It was certainly not, however, the whole story and the LHC experiments are continually improving their measurements of its properties to understand whether it is really the expected Higgs boson or a messenger of new physics. During the current shut-down for upgrade of the LHC, they are still searching for evidence of new particles in their data. One of the most promising possibilities is that the LHC will discover the particle(s) responsible for the Dark Matter that makes up a large fraction of the known material in the Universe. The scientists in our consortium study theories of dark matter, using data from the LHC, dedicated dark matter searches, and astrophysical observations. Any new physics produced at the LHC will be produced as a result of smashing two protons into each other, a very complicated environment, usually in association with "jets" of other particles. Members of our consortium will explore how we can make use of these jets to learn more about the associated new physics: the better we understand the environment in which new physics occurs, the more we are able to learn about the new physics itself. This is a complicated business that often necessitates computer simulations of particle collisions. Our members are experts in these simulations and are making theoretical advances that will underpin improvements in their accuracy, which is essential if we are to make the most of the exciting data from the LHC.
The Standard Model of particle physics is also insufficient when it comes to explaining the early history of the Universe, when it was hot and dense. The evidence is now very strong that the history began with an era of accelerating expansion, called inflation. We are experts on inflation and its consequences. Inflation causes tiny quantum fluctuations in the early Universe, which ultimately grew to become observable effects. One effect is the formation of the billions of galaxies that populate the night sky. Another is to leave a tiny imprint on the cosmic microwave background radiation (CMB), a faint hum of radiation in which the Universe is bathed. The CMB has been studied in exquisite detail by the Planck satellite. We have been at the forefront of interpreting the Planck data's clues about the precise form of the inflationary theory. There is also overwhelming evidence that the expansion of the Universe is currently accelerating. Our scientists are working on particle physics explanations of this expansion, known as Dark Energy theories, and the interplay between them and Dark Matter theories.
The evolution of the Universe itself is governed by Einstein's General Theory of Relativity. This theory also predicts extreme regions in which space is so curved that not even light can escape - black holes (BH). Our scientists are studying the conditions under which BHs are stable, how they affect the interactions of particles around them, including hypothetical extremely light particles called axions, and whether BH solutions are related to the "arrow of time".

Planned Impact

See the attached "Pathways to Impact" document for details.
This project has impact beyond the international scientific community mainly through the training of highly skilled graduate students and postdoctoral researchers and through extensive "outreach" activities of various kinds aimed at engaging directly with the general public, school children, teachers, policy makers and the media. Undergraduate teaching is also impacted beneficially by our research.

Publications

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