Ph.D. Projects in High Energy Physics

Despite accounting for 85% of the mass of the Universe, the nature of dark matter remains a mystery. The LZ experiment, based at the Sanford Underground Research Facility, USA, is at the forefront in the quest to observe galactic dark matter, having recently published the world-leading limits on dark matter interactions. LZ is probing uncharted electroweak parameter space, with the ability to discover or provide constraints on the foremost dark matter theories. This studentship represents an exciting opportunity to participate in the analysis of science data from LZ. The candidate will play an active role in the flagship dark matter search, currently being led by the UCL group, and will have the chance to explore the sensitivity of LZ to more physics beyond the Standard Model, including neutrino-less double beta decay, also led by UCL. In addition to data analysis, the project will involve the use and development of Monte Carlo simulations and statistical inference techniques. There is the potential for the successful applicant to travel to site to assist in the operation of LZ’s 7 active-tonne dual-phase xenon time projection chamber, the world’s largest detector of its kind, as well as to spend extended time at one of our collaborating US, European, or Australian institutions. The student will also engage with design efforts and construction of XLZD, the future global xenon-based rare-event search observatory. XLZD will be the definitive WIMP search experiment, either delivering a historic first discovery, providing a high-statistics confirmation of signal in LZ, or definitively ruling out the standard WIMP hypothesis. XLZD also has immense potential as a rare-event observatory, enabling searches for alternative (non-WIMP) dark matter models, exotic neutrino, and BSM physics inaccessible anywhere else. 

For more information, see our Dark Matter Research page, or contact Dr Amy Cottle or Prof Cham Ghag.

Proton therapy is a more precise form of radiotherapy that provides significant benefits over conventional X-ray radiotherapy, particularly for children. Two new detectors currently under development within the HEP proton therapy group are focussed on improving the accuracy of dose delivery in proton therapy to improve the speed and accuracy of cancer treatment. The QuARC (Quality Assurance Range Calorimeter) measures the proton range with a series of plastic scintillator sheets. The scintillation light output is measured by a series of photodiodes, which are read out by custom ADC boards controlled by an FPGA. The QuADProBE adds beam size and position through orthogonal arrays of scintillating fibres, again read out by photodiode arrays and controlled by FPGA. The intention is to extend this with a novel design of dose monitor from NPL. This will be the first detector in the world that is able to make all the necessary measurements of the clinical proton therapy beam simultaneously.

This project focuses on the development of the QuADProBe, with the inclusion of a detector capable of measuring dose. The QuARC designed is well-advanced, with the front-end electronics and back-end FPGA-based readout system suitably mature. This will be extended to cover the readout of both the scintillating fibre profile monitor and the NPL Transmission Calorimeter for measuring dose. The project offers the possibility of being involved in every step of the detector design and development: this includes the front-end electronics (for both the scintillating fibres and transmission calorimeter), the FPGA firmware, the reconstruction software and the web-based GUI.

The student will be able to focus on the specific areas of this development that best matches their skills but will likely contribute to the majority of the detector development, rather than being restricted to just one aspect. Some experience with detector hardware along with suitable programming skills is highly desirable. There will also be some web development required for the back-end detector control, which is entirely web-based. The student will be expected to accompany the PBT group on experimental runs to clinical facilities and be given the opportunity to learn clinical uses of proton beam therapy and observe patient treatment alongside the experimental work. 

More details on the project can be found on the UCL HEP Proton Therapy Wiki and the Proton Beam Therapy page.

Contact: Prof. Simon Jolly

The study of neutrinos reaching Earth from the edge of the observable universe is transforming our understanding of astrophysical systems at the ultimate frontiers of energy and gravity. Giant neutrino telescopes are soon to come online, marking the start of a new era in Multimessenger Astronomy that promises the discovery of new neutrino sources every year. Moreover, these telescopes will enable the detection of neutrinos from the centre of the Milky Way, a unique environment that will serve as a complementary laboratory for particle physics alongside Earth-based experiments.

This project aims to contribute to the development of one such future neutrino telescope, the Pacific Ocean Neutrino Experiment (P-ONE). It will involve the design and simulation of P-ONE, as well as the analysis of the first data collected during its demonstrator phase. The project will also offer the opportunity to spend extended periods in Vancouver, working on hardware during the assembly and commissioning of the instrument’s detection lines, and to collaborate with theoreticians to explore the discovery potential of future neutrino telescopes.

For more information, visit our Ultra-high Energy Neutrinos page or contact Dr Matteo Agostini.

What is matter? What is its origin? What is it made of? These questions, first posed by ancient Greek philosophers, continue to challenge modern science. Our best theories predict that matter and antimatter are always created in equal amounts, yet the universe is dominated by matter — implying that symmetry-violating processes shaped our existence. Neutrinos, the most abundant matter particles in the universe, are especially intriguing, as they may be their own antiparticles. Their tiny masses, unexplained by the Standard Model, could therefore hold the key to understanding the cosmological matter–antimatter imbalance.

LEGEND is a world-leading experiment studying whether neutrinos are their own antiparticles. This PhD project will focus on developing AI-powered analysis techniques to extract physics results from the current phase of the experiment, as well as on R&D of advanced semiconductor technologies, in collaboration with an industrial partner, for the next phase of the experiment. 

For more information, visit our LEGEND page or contact Dr Matteo Agostini.

The search for physics beyond the standard model is still at full swing at the Large Hadron Collider (LHC). While new particles cannot be guaranteed, it seems at least one is clearly missing, a candidate for dark matter. The realisation that current particle physics deals with only 5% of the matter in the universe is both embarrassing and encouraging.

The ATLAS detector is one of the multi-purpose experiments analysing particles from LHC collisions. The large 50m long apparatus is capable of reconstructing the trajectories of charged particles and measure their momenta and energy with high precision. Hence it is a great place to search for physics beyond the Standard Model, including models that contain a dark matter candidate. Viable models will need to be looked for using unconventional signatures, in particular long-lived particles (LLP) decaying late in the detector. This project will look for LLPs, using the expertise of the UCL group on tracking and advanced methods to identify such particles.

For more information, visit our ATLAS page or contact Prof Andreas Korn.

The search for physics beyond the Standard Model (BSM) is the defining aim of particle physics today, and precision muon measurements offer sensitivities to BSM far beyond the direct reach of the Large Hadron Collider. The Mu3e experiment will search for flavour violation in the charged lepton sector: lepton flavour violation has already been observed in neutrino oscillations, and is predicted in the charged lepton sector by a range of BSM models.

Using an innovative, ultra low-mass tracker, Mu3e will perform the world's most sensitive search for the neutrinoless decay of an antimuon to two positrons and one electron, improve sensitvities by a factor of 10,000 over current limits and probing for new physics at mass scales beyond 1,000 TeV. This step-change in sensitivity brings the potential of a ground-breaking discovery when Mu3e begins data-taking in 2026.

 A PhD on Mu3e would involve:

• A stay at the Paul Scherrer Institut (Switzerland), during Mu3e data-taking;
• Analysis of the first Mu3e data, including the optimisation of algorithms to increase the sensitivity, including the potential to deploy machine learning, and preparation of the second round of data-taking
• Perform the first search for the three-electron signal, and explore the data for other potential signs of new physics.

For more information, visit our Lepton Flavour Physics page, or contact Prof. Gavin Hesketh.

The ATLAS experiment is measuring new physics processes above the electroweak symmetry-breaking scale, extending the energy frontier of knowledge. A key question is - how successful is the Standard Model at these energies? Does the physics developed at lower energies continue to work at high energies? Or will these measurements reveal physics new phenomena?

This project will tackle that question by joining the measurement programme at the ATLAS experiment at the CERN Large Hadron Collider, and using the UCL-developed "Contur" programme to compare the data to state-of-the-art predictions from the Standard Model and beyond. 

We are currently making a first measurement of inclusive tri-lepton production in the electron and muon channels, and recently published the first measurement of include di-tau production. This project will aim to exploit run 3 data to bring these experiences together, making a more complete measurement of the di-tau phase space and including taus in the tri-lepton measurement, probing the Standard Model and beyond new phase space. 

There is also the possibility of co-supervision from colleagues at the T.D.Lee institute in Shanghai, who collaborate with us on ATLAS and are measuring the rare W->trilepton decay. This would include spending time at the institute in Shanghai, as well as at CERN.

For more information, visit our ATLAS page or contact Prof Jon Butterworth.

The Deep Underground Neutrino Experiment (DUNE) at Fermilab and the Sanford Underground Research Facility (USA) will be the world’s leading facility for exploring the fundamental nature of neutrinos. This PhD project will perform the analysis of DUNE’s first data from atmospheric neutrinos, using these naturally produced neutrinos to study oscillations over a wide range of energies and baselines. Atmospheric neutrinos provide an independent and complementary probe of the neutrino mass ordering, the mixing angle θ23, and CP-violating effects, while also enabling novel studies such as neutrino propagation through the Earth’s interior. In tandem, by contributing to UCL’s leading role in DUNE’s Data Acquisition (DAQ) and Data Quality Monitoring (DQM) systems, this research will ensure the precision and stability required for low-energy neutrino detection. Through advanced data analysis, detector performance studies, and involvement in DUNE’s monitoring and calibration activities, the project will enhance DUNE’s sensitivity to low-energy neutrinos. By doing so, this project will help transform DUNE into a global neutrino observatory, capable of detecting signals from the Sun, supernovae and beyond. This is a rare opportunity to join a world-leading U.S. experiment at a pivotal moment, with funding available to support extended research placements in the USA, and to contribute to a high-impact scientific mission with real potential to push the frontiers of particle physics and cosmology.

For more information, visit our DUNE page or contact Dr. Alex Keshavarzi

NOvA is one of two currently operating long-baseline neutrino oscillation experiments. DUNE is one of two currently under construction long-baseline neutrino oscillation experiments. These experiments represent one of the best opportunities to use quantum-mechanical mixing over thousand-kilometre baselines for precision testing of the standard model of particle physics.

Already with 10-years of data NOvA has produced the best single experiment measurement of the largest of the neutrino mass differences. The final NOvA dataset will be analysed during the course of this PhD project. To extract the maximum scientific information from this dataset, innovative analysis techniques and particularly energy-estimation algorithms will be developed and implemented. On DUNE, the student will have the opportunity to participate in the commissioning and first data taking of this next-generation experiment. 

For more information, visit our Long-baseline Neutrino Oscillations page or contact Prof. Ryan Nichol.

Soil carbon sequestration offers major potential to mitigate anthropogenic greenhouse gas emissions. Enhanced weathering of silicate rocks can boost CO₂ capture while benefiting agriculture and creating commercial opportunities. However, its success depends on accurately quantifying the sequestered CO₂, and current methods are slow, invasive, and labour-intensive.

This PhD project, based at UCL HEP in collaboration with UNDO, will apply advanced particle physics technologies to environmental monitoring by developing a novel neutron-induced gamma spectroscopy (NGS) system for rapid, quantitative, in situ carbon assessment over large areas. Building on ongoing conceptual work, the project will progress to the technical design of an NGS apparatus through detailed simulations and bench measurements, with potential first field trials to evaluate performance and feasibility.

The role suits a candidate with strong experimental aptitude and interests spanning simulation, software development, and detector instrumentation.

For more information, please contact Prof. Ruben Saakyan.

Higgs pair production (HPP) is arguably the most exciting research topic at the LHC and the flagship physics process for the HL-LHC programme, yet to be observed. Non-resonant HPP is our best probe to the Higgs self-interaction, which will help shed light on the shape of the Higgs potential, the nature of electroweak phase transition, and ultimately the evolution of our universe in the early moments after the Big Bang. Resonant HPP is a sensitive probe for new physics at the energy frontier.

UCL pioneered the early searches at the LHC for HH->4b, one of the most sensitive channels to look for HPP, and has been playing a leading role within ATLAS in this search to this day. Your project will focus on (a) developing/implementing novel ML techniques for modelling the background and for maximizing the signal vs. background classification; (b) the combination of the HPP results from all the different final states (which will be a major focus of work leading up to the first observation of HPP with the full Run2+Run3 datasets); and (c) the interpretation of results for new physics, in terms of probing key couplings in the Higgs effective field theory formalism.

As always, the project will include a more technical element of work. For this, you will have the opportunity to contribute to the development of novel, ultra-fast ML algorithms for the Global Hardware Trigger of ATLAS for HL-LHC, where UCL has been playing a major role. As part of this work, you will be at the heart of shaping the ATLAS Trigger strategy for HL-LHC, which is crucial for the HPP study, but also for the entire physics programme of ATLAS at HL-LHC. How you split your time between the physics analysis work and the more technical work will depend on your skills, strengths and interests.

There is also the possibility of co-supervision of this project with colleagues at the T.D.Lee Institute in Shanghai, who collaborate with us on ATLAS and also have a strong record and interest particularly in combining the HPP search results from different final states. This would include spending time in Shanghai, as well as at CERN.

The timing for the above work is ideal. It is both a great opportunity to be at the heart of the first-ever observation of HPP, and at the same time, to build expertise that will serve your career well, as by the time you will be finishing your PhD in ~2030, it will be the start of Run4 and the HL-LHC programme and your contribution to the Global Hardware Trigger system will put you in a great position for your next career step.

For more information, visit our ATLAS page or contact Prof. Nikos Konstantinidis.