Manchester Particle Theory Consolidated Grant 2022 : Particle Physics in Colliders and the Cosmos

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

Abstract

Particle physics has an ambitious goal : to understand our Universe at the most fundamental level. This means discovering all the elementary particles which are the ultimate building blocks of matter, and understanding the laws that govern their interactions. The current theory is known as the Standard Model of particle physics and it has enjoyed decades of remarkable success in explaining experimental data from all the high-energy particle collider experiments to date, including data from the current LHC at CERN. Yet it is also abundantly clear that there exists physics beyond the Standard Model which has eluded us and awaits discovery. For instance it is known that a large fraction of the material Universe is made up of "dark matter" which cannot be explained within the Standard Model. Our scientists are experts in Standard Model physics as well as in theories of particle physics beyond the Standard Model and their possible manifestation in colliders and cosmological data. We propose to exploit this expertise to maximise the prospects for discovery of new physics.

One of the main routes to discovery involves confronting precise LHC data with equally precise theoretical predictions to look for deviations from the current theory, which would signal new physics. The landmark discovery of the Higgs boson, which deals with the origin of mass, offers an exciting avenue for further exploration. Often described as the last piece of the Standard Model jigsaw, the true nature of this particle is yet to become clear, and any deviation from the textbook Higgs boson could signal new physics. Our expertise in the theory of strong interactions (QCD) is critical for such studies at the LHC, which smashes together protons at high energies and where strong interactions are all pervasive. We specialise in the construction of algorithms which derive from QCD and lead to a full computer simulation of LHC collisions that can be directly compared to data. One of the proposed aims of our research is to design novel QCD based algorithms which improve the current state of the art in a variety of ways. We are also experts in the physics of "jets" which are formed in LHC collisions. In our proposal we aim to develop new methods that will enable us to distinguish jets produced by Standard Model particles from those arising from new particles, thereby enhancing the discovery potential of the LHC.

If deviations from Standard Model expectations are seen in experimental data, we need to be able to interpret them in terms of theories of physics beyond the Standard Model. Our proposed research involves the continued construction of compelling models of new physics and investigating their signatures at the LHC. Another part of our research consists of actively pursuing some of the key questions that the Standard Model has left unanswered. One such question concerns the excess of matter over antimatter in our Universe and we propose to investigate directly related questions using the latest LHC data. Another direction involves searches for new particles, at colliders and elsewhere, that might be candidates for dark matter. Our scientists, with expertise in theories of dark matter, propose to study LHC data together with astrophysical observations and dedicated dark matter searches in order to discover the origin of dark matter. Yet another area where the Standard Model is inadequate is for explaining the "dark energy" that is responsible for the accelerated expansion of the Universe, for which there is overwhelming evidence. We propose to study dark energy theories and to develop them further, alongside their interplay with dark matter theories.

All our proposed work involves combining cutting-edge theoretical ideas and techniques with rigorous methodology and the most precise data from colliders and cosmology. We thus believe that achievement of our goals will equate to scientific progress that shall be of lasting value to our field.

Publications

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