UK Universities Shine in Muon g-2 Breakthrough Prize Victory

Renowned researchers from leading United Kingdom universities have been recognized with the 2026 Breakthrough Prize in Fundamental Physics for their pivotal roles in the Muon g-2 experiment. This prestigious award, often dubbed the 'Oscars of science,' celebrates decades of groundbreaking work aimed at measuring the muon's anomalous magnetic moment with unprecedented precision. Institutions such as University College London (UCL), the University of Liverpool, and Lancaster University stand at the forefront of this international triumph, highlighting the strength of British higher education in particle physics.

The prize, valued at $3 million and shared among approximately 350 living collaborators, underscores the collaborative spirit driving fundamental physics research. For UK academics, this accolade not only validates years of dedication but also bolsters the profile of physics departments nationwide, attracting top talent and securing vital funding streams.

Understanding the Muon g-2 Experiment: A Deep Dive

The Muon g-2 experiment probes one of the most elusive properties of subatomic particles. The muon, a heavier cousin of the electron discovered in 1936, possesses an intrinsic magnetic moment characterized by the g-factor. In the Standard Model of particle physics—the cornerstone theory describing fundamental forces and particles—this g-factor should be exactly 2 for a point-like spin-1/2 particle. However, quantum corrections from virtual particle interactions cause a tiny deviation, quantified as the anomalous magnetic moment a_μ = (g - 2)/2.

To measure a_μ, scientists accelerate muons to near-light speeds and inject them into a superconducting magnetic storage ring. As the muons circulate, their spins precess due to the magnetic field. Straw tube detectors precisely track their decay products (positrons), revealing the precession rate. The full process involves: (1) muon production via pion decay, (2) beam cooling and injection, (3) spin precession monitoring over thousands of laps, (4) data analysis correcting for magnetic field uniformity and electric focusing fields, and (5) comparison with theoretical predictions computed via quantum electrodynamics (QED), electroweak theory, and hadronic contributions.

UK universities excelled in detector construction, software for data analysis, beam simulations, and theoretical inputs, ensuring the Fermilab measurement reached a precision of 0.20 parts per million—the most accurate ever.

Six Decades of Pursuit: From CERN to Fermilab

The journey began in the late 1950s at CERN, where initial measurements confirmed Standard Model expectations. By the 1970s, CERN's IHEP-MOM collaboration refined techniques, achieving higher precision. In the 1990s, the experiment relocated to Brookhaven National Laboratory's Alternating Gradient Synchrotron (AGS), yielding a 2006 result hinting at a 3.4 sigma discrepancy with theory—potentially signaling new physics.

Fermilab took the baton in 2013, relocating the 14-meter storage ring and upgrading detectors. Data collection ended in 2018, with final analysis published in 2025 confirming the anomaly at around 4.2 sigma before theoretical updates. Recent lattice QCD computations resolved some tensions, but discrepancies between data-driven and lattice-based hadronic vacuum polarization persist, fueling debate.

Throughout, UK contributions remained steadfast, with physicists from UCL, Liverpool, and Lancaster adapting to each phase's challenges.

UCL's Trailblazing Detector and Analysis Expertise

At UCL's Department of Physics & Astronomy, Professor Gavin Hesketh leads the Muon g-2 group, which built critical straw tube trackers for the storage ring and developed sophisticated software for positron tracking and pattern recognition. Funded by the Science and Technology Facilities Council (STFC) and the Royal Society, UCL's efforts spanned hardware prototyping in London labs to on-site commissioning at Fermilab.

Dr Rebecca Chislett highlighted the teamwork: “Reaching the final result involved a phenomenal amount of work... including some of our graduate students.” Current and former members like Dr Lucy Bailey, Dr Alex Keshavarzi, and PhD student Matthew Warren share the prize. This marks UCL's second Breakthrough Prize in two years, following the 2025 ATLAS Higgs award, cementing its status in high-energy physics.

UCL's ultra-precise particle measurements program now trains dozens of PhD students annually, fostering careers in academia and industry.

University of Liverpool: Largest UK Group at Fermilab

The University of Liverpool hosted one of Europe's largest Muon g-2 teams—28 strong, including 17 current members—contributing to accelerator physics, tracker detectors, and theory. Professor Themis Bowcock initiated Liverpool's involvement, while Professor Graziano Venanzoni served as Fermilab spokesperson during peak data-taking.

Dr Joe Price, current lead, emphasized: “These high precision measurements are only possible with world class detectors...” Supported by Leverhulme Trust and STFC, Liverpool's work advanced from Brookhaven to Fermilab operations. This is their fourth Breakthrough Prize link in 15 years, spanning neutrinos, Higgs, and LHC.

The department now eyes MUonE at CERN, with Dr Saskia Charity noting its role in resolving theory tensions. Liverpool's program inspires undergraduates through summer placements and PhD scholarships.

Lancaster University's Accelerator Simulations

Dr Ian Bailey at Lancaster University and the Cockcroft Institute spearheaded computer simulations modeling muon beam dynamics from Fermilab accelerators into the storage ring. These ensured optimal injection and minimized systematic errors, vital for 0.20 ppm precision.

Bailey reflected: “It's great to see all the hard work... recognised by the Breakthrough Prize.” Lancaster's interdisciplinary approach blends accelerator science with particle physics, training engineers for roles at CERN and Diamond Light Source.

This win elevates Lancaster's profile, drawing EU and UKRI grants for future muon facilities.

Profiles of Prize-Winning UK Researchers

• Prof Gavin Hesketh (UCL): Leads detector R&D; quote on curiosity driving discovery.
• Prof Graziano Venanzoni (Liverpool): Former spokesperson; praises collective expertise.
• Dr Ian Bailey (Lancaster): Simulation pioneer; highlights cross-community collaboration.
• Dr Rebecca Chislett (UCL): Data analysis expert; credits grad students.
• Prof Thomas Teubner (Liverpool): Theory Initiative co-founder; addresses prediction inconsistencies.

These academics mentor PhDs, publish in Nature and Physical Review, and secure ERC grants, exemplifying career paths in UK physics.

Boost for UK Higher Education and Particle Physics

The prize injects prestige and potential funds into UK universities amid STFC budget pressures. Physics departments report increased PhD applications—UCL saw 20% rise post-prize. It positions Britain as a muon physics hub, rivaling US labs.

Impacts include enhanced employability: Muon g-2 alumni lead at UKAEA, National Physical Laboratory, and firms like Siemens Healthineers. For students, it spotlights interdisciplinary skills in demand for quantum tech and AI-driven analysis.

Training Future Physicists: PhD and Career Opportunities

UK involvement trained over 50 PhDs since 2010, many now lecturers or industry leads. Programs like Liverpool's STFC-funded studentships offer Fermilab placements, blending experiment and theory.

• Hands-on detector building
• Advanced Python/Machine Learning for analysis
• International collaborations via grid computing

Post-prize, universities eye expanded cohorts, with UCL launching muon-focused MSc modules.

STFC Funding: Backbone of UK Success

The Science and Technology Facilities Council provided £10M+ for UK Muon g-2 efforts, funding beamlines, travel, and computing. This investment yields 200+ publications, training 100+ early-career researchers.

As UKRI reallocates post-Horizon Europe, prizes like this advocate sustained particle physics support, vital for net-zero tech and medical imaging.

Looking Ahead: MUonE and New Physics Horizons

UK teams pivot to MUonE at CERN, measuring muon-electron scattering to refine hadronic contributions. Liverpool and UCL lead proposals, with first beams by 2028.

If discrepancies persist, it could herald supersymmetry or dark matter hints. For UK higher ed, this sustains excellence, inspiring STEM enrollment amid global talent wars.

Photo by National Cancer Institute on Unsplash

This Muon g-2 triumph reaffirms UK universities' global leadership, nurturing innovators for tomorrow's discoveries. Aspiring physicists, explore opportunities at these institutions to join the quest.