Particle Physics Consolidated Grant 2021

Particle physics seeks to understand the Universe, its birth, evolution, and fate in terms of elementary particles (quarks, leptons), the fundamental forces (strong, electromagnetic, weak forces, gravity) and the particles that mediate them (photons, W/Z, gluons, gravitons) and the Higgs particle that gives elementary particles mass. The Standard Model, a theoretical framework developed in the last fifty years, elucidates almost all particle-physics data. But the model is incomplete. It explains what we encounter on Earth, but studies of the cosmos suggest the presence of mysterious dark matter that holds galaxies together and more mysterious dark energy that is driving galaxies apart at an ever-increasing rate. Oxford's research will significantly advance our understanding of the "new-physics" theory that will emerge to replace the Standard Model by providing the data to guide the theoretical work to develop it. The Large Hadron Collider (LHC) reproduces the conditions within a million millionth of a second of the Big Bang. Oxford plays a major role in ATLAS and LHCb. These experiments have the potential to revolutionise our understanding of the Universe completely. In ATLAS, Oxford physicists participated in the exciting discovery of the "Higgs particle", which gives mass to elementary particles. The Higgs particle is like a curtain; now that we have found it, we can draw back the curtain to see a new world. Accordingly, we are studying it in great detail. We are also searching for new particles that would provide a solution to "dark-matter" that makes up about 80% of matter in the Universe. Oxford physicists on LHCb strive for a better understanding of the origin of the matter-antimatter asymmetry in the Universe by studying subtle differences in the behaviour of quarks & antiquarks - "CP-violation". This asymmetry permits us to exist. Over the next decade, the LHC will reach higher energies and intensities requiring detector improvements for ATLAS & LHCb. The upgraded detectors will take particle physics to an unprecedented level of sensitivity for the nearly inevitable new-physics observations. We use powerful computing resources and develop cutting-edge analysis tools necessary to extract essential discoveries from vast data volumes. We participate in high-precision experiments complementary to the large experiments at the LHC. Mu3e searches for new physics mediated by very heavy particles that would not be visible at the LHC but are expected in many theoretical models, including SUSY. LZ addresses one of the most critical questions in particle physics & cosmology by searching for dark matter. LSST will measure how quickly the expansion of the Universe is speeding up due to the mysterious dark energy that represents 75% of all energy in the Universe and acts like anti-gravity pushing galaxies apart. Through T2K, SK, HK, DUNE, & future projects, Oxford aims to understand the elusive neutrino, its "oscillation" from one type to another, and whether there is a difference between neutrino and anti-neutrino properties - "CP-violation". SNO+ will measure other properties of the neutrino, e.g. whether or not it is its own antiparticle. Quantum sensor technologies have the potential to change our approach to understanding the Universe radically. We are building the first large-scale atom interferometer in the UK to search for light dark matter particles and gravitational waves (AION). We are also part of MAGIS-100, a 100 m tall device under construction at Fermilab in the US. We will continue to improve our instrumentation capabilities to retain the ability to construct the most sophisticated apparatus for our experiments. We will maintain our world-leading role for scientific excellence & major state-of-the-art detector construction in particle physics for the future. These are exciting times for particle physics, and Oxford is playing a major role.