Higgs Bosons and dark matter: Birmingham’s Swiss role in unlocking the mysteries of the universe

It’s hard to overestimate the importance of the Higgs boson. Without this enigmatic aspect of nature, no particles would have mass, meaning no stars, no planets, and no human life.

Birmingham scientists have already shared in the intense excitement accompanying the discovery of the Higgs boson and much more. With a strong ongoing presence of its particle physicists in Geneva, the University is set to help unlock many more of the universe’s darkest secrets over the coming years.

British theoretical physicist Peter Higgs came up with the idea of the Higgs Boson, but it took the concerted efforts of an international team of scientists and a very large, extremely complicated piece of scientific equipment to prove its existence.

Buried 100 metres beneath the Swiss-French border, the Large Hadron Collider (LHC) is the world’s most powerful particle accelerator, operated by CERN, the European Laboratory for Particle Physics. A 27 km ring of superconducting magnets and accelerating structures, the LHC smashes counter-circulating beams of protons together at more than 99.999999 per cent of the speed of light and scientists observe the new particles created.

The particle physics equivalent of launching sewing needles from either side of the Atlantic and getting them to collide at the mid-way point, using the LHC allowed scientists to discover the Higgs boson on 4 July 2012. Their discovery confirmed the existence the mechanism that gives rise to mass and completed the Standard Model of Particle Physics, an incredibly well-validated theory of the subatomic world.

CERN was established in 1954 by 12 founding member states in Western Europe, and the University of Birmingham has been involved with particle physics research at the Geneva-based organisation for over 70 years – more than half of the University’s 125-year history. The University has one of the UK’s largest particle physics groups – with a history stretching back to the 1950s - and a key figure in its involvement with CERN has been Emeritus Professor John Dowell.

Professor Dowell graduated from the University of Birmingham in 1952 and went on to work at Birmingham, before retiring as Professor of Elementary Particle Physics in 2002. His connections to CERN go back to the organization’s early years and Professor Dowell helped develop detectors for the LHC at Geneva, as well as being involved in the ATLAS experiment which discovered the Higgs Boson.

Birmingham today has a strong presence of particle physicists at CERN, with a central involvement ATLAS, where our scientists are further investigating the Higgs boson, investigating ultra-rare decays of strange particles in quantum loops, and searching for dark matter.

Dr Paul Thompson has worked in the Birmingham particle physics group for over 20 years and is currently working on ATLAS. A Birmingham alumnus at both undergraduate and postgraduate level, Paul is highly experienced in data analysis techniques, particularly relating to Higgs physics, and has been at CERN for five years following a stint at DESY (Deutsches Elektronen-Synchrotron), in Hamburg. Paul is currently working on installing upgraded trigger equipment that will control the 25 million proton-proton crossings per second when the LHC starts its next run.

“I got into this field during the final year of my physics degree at Birmingham, when I studied a module on particle physics delivered by John Dowell – from those beginnings my science journey has brought me to CERN,” explains Paul. “Triggering is an important part of our work - a system that rapidly decided which events in a particle detector to keep when only a small fraction of the total can be recorded. Without triggering, we would have no data.”

Eric Liu is a third-year PhD student working within the ATLAS experiment. Some of his six months at CERN has been spent working on vital testing for upgrades to give the particle detector a new lease of life using silicon-based technology. After completing an integrated Master's degree at Birmingham, Eric began life as a PhD student.

“I’m also looking at quark science as part of my work and have a particular interest in charm quark production,” says Eric. “After I complete my PhD at Birmingham, I hope to secure a postdoctoral position in particle physics. We only understand five per cent of our universe and there is so much more to explore.”

That five per cent accounts for visible matter, but it is believed that the remaining 95 per cent of the universe is made up of ‘dark matter’ and ‘dark energy’. An invisible and hypothetical 'substance’ that does not interact with light or other electromagnetic radiation, dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be observed.

Post-doctoral researcher Dr. Felicia Volle and PhD student Ellie Whiter are both searching for dark matter as part of the LHCb experiment, but their paths to the Birmingham group at CERN are different. After completing her Master's degree at the University of Freiburg, in Germany, Felicia gained her PhD from Université Paris-Saclay, before joining Birmingham’s particle physics team. A graduate of the University of Exeter, Ellie studied for her Master’s at Imperial, before coming to Birmingham for her PhD.

“We don’t know what dark matter is, but our goal is to search for evidence that supports or refutes the existence of dark photons,” says Felicia. “The LHCb detector is recording a massive amount of data from proton-proton collisions at the LHC, which we’re using to make critical tests of just how closely matter and antimatter obey the same laws. If we could prove the existence of dark matter, that would be a game changer in broadening our understanding of the universe.”

Ellie’s work involves searching for new types of particles. A second-year PhD student, her year at CERN allows Ellie to discuss advances in particle physics with fellow scientists from around the world – all sharing a common goal of discovering new physics.

“There are lots of questions but no clear solutions, and we are trying to let the data lead us to new discoveries and proofs,” explains Ellie. “We analyse data from the LHC in the context of different theories, such as supersymmetry, to uncover new aspects of the universe. It’s a weird, but exciting time for physics as we use different search methods, even within the same experiment!”

The University also has a pivotal role in CERN’s NA62 experiment, which in 2024 discovered the rarest particle decay ever observed. Dr. Karim Massri, a former Birmingham PhD student and postdoctoral researcher, is now the physics co-ordinator for the experiment and a lecturer at Lancaster University, regularly welcoming students, postdocs and researchers from his West Midlands alma mater to CERN.

“We’re looking for rare processes - such as NA62’s first experimental observation of the ultra-rare decay of the charged kaon into a charged pion and a neutrino-antineutrino pair - as they are very sensitive to new particles,” says Karim. “We know that the Standard Model is incomplete, as it cannot explain dark matter or the matter-anti-matter asymmetry of the Universe. Studying these rare decays helps us to fill gaps in the Standard Model and possibly discover new physics.”

Another experiment with leading Birmingham involvement is ALICE (A Large Ion Collider Experiment), which specialises in “heavy-ion” physics at the LHC to study the physics of strongly interacting matter at extreme energy densities, where a phase of matter called quark-gluon plasma (QGP) forms.

Nicholas Karatzenis is a second-year PhD student at Birmingham. A graduate of the University of Ioannina, in Greece, with family connections to the city of Birmingham, Nicholas is currently analysing data contributing to our understanding of the formation and evolution of QGP, drawing on data flowing out of the ALICE experiment.

“We’re trying to better understand QGP and why it produces an enhancement of strange quarks – especially in small systems, as these systems weren’t expected to exhibit this behaviour,” explains Nicholas. “CERN is a great place to work within a highly productive scientific environment. There’s always a great feeling of validation when the data confirms the theory, but most exciting is when it doesn’t which may indicate something we don’t yet understand and need to investigate.”

Like the particles travelling at close to light speed below the Swiss-French landscape, the science at CERN remains in constant motion. Data-taking will pause in mid-2026 for a few years to allow major performance upgrades of both the experiments and the LHC itself, with more than a decade of the best data still to come. University of Birmingham particle physicists will play their part in both the upgrade process and the data analysis to learn more about dark matter, ultra-rare particles and the unseen forces that comprise our Universe.