School of Physics and Astronomy

Ion decay sheds light on solar neutrino flux.

Detecting neutrinos

The Sun, the life-sustaining engine of Earth, generates energy through nuclear fusion while releasing a continuous stream of neutrinos—particles that serve as messengers of its internal dynamics. Although modern neutrino detectors unveil the Sun’s present behaviour, significant questions linger about changes in the sun’s release of neutrinos over the course of its existence.

To address these uncertainties, the LORandite EXperiment (LOREX) stands as the final bastion of neutrino geochemical projects. This low-energy solar neutrino detector aims to measure solar neutrino flux averaged since the formation of the sun.

Ion decay

Neutrinos produced in our Sun interact with thallium (Tl) atoms, present in the lorandite mineral (TlAsS2), and convert them into lead (Pb) atoms. The isotope 205Pb is particularly interesting due to its long half-life time of 17 million years, making it essentially stable over the 4 million years timescale of the lorandite ore. As it is currently not feasible to directly measure the neutrino cross-section on 205Tl, researchers came up with a clever method to measure the relevant nuclear physics ingredients: they exploited the fact that fully ionized 205Tl81+ spontaneously decays by bound-state beta decay to 205Pb81+, delivering the information needed for the determination of the neutrino cross section.

The international team discovered that the half-life of 205Tl81+ beta decay was measured as 291 (+33/-27) days. The experiment was only possible thanks to the unique capabilities of the Experimental Storage Ring at GSI in Germany.

This achievement lays the nuclear physics foundation for the LOREX project, which aims to unlock insights into the Sun’s evolutionary history and its connection to Earth’s climate over millennia.

Dr Ragandeep Singh Sidhu, a key contributor to the study and the first author of the publication, highlighted its significance:

This experiment highlights how a single, albeit challenging, measurement can play a pivotal role in addressing significant scientific questions related to solar neutrinos.

The publication is dedicated to the memory of late colleagues Fritz Bosch, Roberto Gallino, Hans Geissel, Paul Kienle, Fritz Nolden, and Gerald J. Wasserburg, whose contributions were integral to the success of this project.

Congratulations to students who received medals, certificates, prizes and scholarships at the School’s Undergraduate and MSc Student Awards Ceremony.

Head of School Professor Philip Best and former Head of School Professor Jim Dunlop announced the awards in recognition of excellent performance and achievement from undergraduate and MSc students during the past two academic years.

Certificates & Medals

207 pre-honours students (years 1 & 2) received Certificates of Merit for outstanding marks in their pre-honours courses. Class Medals are awarded to individuals who received the highest overall mark for their degree programme, with 42 undergraduate and 8 MSc students in receipt of Class Medals.

Prizes and Scholarships

The School has a number of Prizes and Scholarships to award, including a prize for the best final year honours Astrophysics student and a prize for the fourth year student who attains the top mark across all programmes.  29 Prizes and Scholarships were awarded in total to the undergraduate students who achieved outstanding results in their subject area or year. 

Many congratulations to all recipients.

Galaxy mapping data also test how gravity behaves at cosmic scales.

Mapping galaxies

Scientists, including astrophysicists from the University of Edinburgh, used the Dark Energy Spectroscopic Instrument (DESI) to map how nearly six million galaxies cluster across up to 11 billion years of time.

Their complex analysis of DESI’s first year of data provides one of the most stringent tests yet of Einstein’s famous theory of General Relativity and how gravity behaves at cosmic scales.

Looking at galaxies and how they cluster throughout time reveals how the universe’s structure has grown. This allowed DESI’s scientists to test theories of modified gravity – an alternative explanation for our universe’s accelerating expansion typically attributed to dark energy.

They found that the way galaxies cluster is consistent with our standard model of gravity and the predictions made by Einstein.

The result validates the leading model of the universe and limits possible theories of modified gravity, which have been proposed as alternative ways to explain unexpected observations such as the expansion of the universe.

Dr Samuel Brieden, Postdoctoral Research Associate in Observational Cosmology, Institute for Astronomy, University of Edinburgh, said:

The tests used a technique to hide the results from the scientists until the analysis pipeline was frozen, mitigating any unconscious bias. Seeing the final, ‘unblinded’ results was exhilarating. It felt like years of research culminating into that single moment.

Neutrino influence

A further insight DESI has revealed is on the mystery of neutrino mass. Neutrinos are elementary particles with very small masses, but the force of gravity they collectively produce affects how galaxies move and cluster in space. The DESI dataset has made it possible to detect the effect of neutrinos, which is exciting for both cosmologists and particle physicists.

About DESI

DESI can capture light from 5,000 galaxies simultaneously. It sits atop the US National Science Foundation’s Nicholas U Mayall 4-metre Telescope at Kitt Peak National Observatory, in Arizona, USA.

DESI is managed by the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab). UK involvement in DESI includes Durham University, University College London and the University of Portsmouth as full member institutions, together with individual researchers at the universities of Cambridge, Edinburgh, St Andrews, Sussex and Warwick. 

The experiment is now in its fourth of five years surveying the sky and plans to collect data on roughly 40 million galaxies and quasars by the time the project ends.

Edinburgh involvement

While mostly members of the research group led by Professor Florian Beutler (including Dr Samuel Brieden, Dr Richard Neveux, and Dr Mike Shengbo Wang) actively contributed to the study released today, also the groups led by Dr Yan-Chuan Cai, Professor Sergei Koposov, Professor John Peacock, and Professor Alkistis Pourtsidou are deeply involved in the DESI collaboration in various aspects, from investigating the structure of the Milky Way up to testing cosmological models on the largest scales.

Award funds will support Dr Wood’s business ventures in utilising scientific advancements to address societal challenges.

Dr Wood is passionate about using the physics of complex fluids to develop new innovations that will help people live more sustainably and in better health. She has received an Innovate UK Women in Innovation award which will further support her business ventures.

Biotech business

She is the co-founder of biotech business Dyneval which works to improve the profitability and sustainability of farming. In 2022, Dyneval launched the Dynescan, the first semen analyser able to measure the lifetime of semen in conditions similar to the reproductive tract. Tiffany and her co-founder, Dr Vincent Martinez developed this technology from the soft matter physics labs at the University of Edinburgh through to market, and it is bringing exciting new data insights to fertilisation capacity through its automated, precise and reproducible measurements.

Innovative technology

Dr Wood is the inventor of DAINTech, an innovative new gel phase formulation chassis technology that offers long-term stability and unique and beneficial flow characteristics without the use of synthetic polymers. It offers an alternative potential solution to formulate otherwise challenging ingredients and is expected to be broadly applicable to a wide range of industry applications.

Complex fluids

She is also the co-founder and former Director of the Edinburgh Complex Fluids Partnership (ECFP), which specialises in understanding the interactions between components in soft materials and complex fluids and how they influence product behaviour. Through this understanding, the group helps companies optimise product performance, solve manufacturing challenges, and switch to more sustainable resources and efficient processes. 

Women in Innovation award

The Innovate UK Women in Innovation award was launched in 2016 to encourage more women to apply to Innovate UK funding opportunities. The programme supports women across the UK to fully realise their vision for their businesses and make a real difference to the world through innovation.

Dr Wood accepted her award plaque from the Innovate UK Business Connect team on the 7 November and afterwards gave an inspiring seminar for students and staff titled 'The power of physics: improving efficiencies and sustainability for a better future'.

Team successfully measure the bound-state beta decay of fully-ionized thallium-205 ions.

How long did it take for our Sun to form within its stellar nursery? An international team of scientists has come closer to finding out.

Radioactive nuclei with lifetimes on the order of millions of years can reveal the formation history of the Sun and active nucleosynthesis occurring at the time and place of its birth. Among such nuclei whose decay signatures are found in the oldest meteorites, lead-205 is a powerful example. However, making accurate abundance predictions for lead-205 has so far been impossible because the weak decay rates are very uncertain at stellar temperatures.

To constrain these decay rates, a team of scientists measured the bound-state beta decay of fully ionized thallium-205 ions, an exotic decay mode that only occurs in highly charged ions. Work took place at the Experimental Storage Ring at the GSI/FAIR facility in Germany.

With new, experimentally backed decay rates, they used stellar models to calculate lead-205 yields. They found positive isolation times that are consistent with the other short-lived radioactive nuclei found in the early Solar System.

The results reaffirm the site of the Sun’s birth as a long-lived, giant molecular cloud and support the use of the lead-205–thallium-205 decay system as a chronometer in the early Solar System.

Dr Ragandeep Singh Sidhu, the study’s second author, who is based in the School’s Nuclear Physics research group said:

This significant result enhances our understanding of how radioactive lead-205 is produced in asymptotic giant branch stars and sheds light on the timescale of the Sun’s formation.

The results have been published in Nature.

Prize funds will be used to carry out research in topological problems in soft matter physics.

The Philip Leverhulme Prize is awarded to researchers at an early stage of their career, whose work has had international impact and whose future research career is exceptionally promising.

Dr Michieletto’s background is in polymer and statistical physics and he has a track record in using both simulations and experiments. His current main line of research is inspired by how the genome in our cells is mechanically and topologically manipulated by proteins, and he is focused on discovering new DNA-based soft materials and complex fluids that can change topology in time.

Dr Michieletto will use funds from the Philip Leverhulme Prize to continue his group’s research on the use of artificial intelligence and machine learning to classify knots. Although mostly focused on understanding the mechanisms through which AI learns mathematical ‘topological invariants’, this research can also have applications to protein folding, genome organisation and even drug design. 

A spacecraft has revealed the first section of what is set to be the largest 3D map of the Universe ever made.

The Euclid space telescope – orbiting one million miles from Earth – has produced a piece of its cosmic map containing some 14 million galaxies and tens of millions of stars in our own Milky Way. Despite its vast scale, the section accounts for just one per cent of the full map that Euclid will produce during its six-year mission.

The mission – launched in July 2023 – is led by the European Space Agency and a consortium of more than 2,000 scientists from 16 countries, including researchers from the University of Edinburgh.

Map section

The newly released map section – 208 gigapixels in size – is composed of 260 observations made by Euclid’s powerful cameras in Spring of this year.

Researchers will use data gathered by the mission to shed light on two of the biggest mysteries in the Universe: dark matter and dark energy. Dark matter – which does not reflect or emit light – is thought to make up around 80 per cent of all the mass in the Universe and binds galaxies together. Dark energy is a mysterious phenomenon that is pushing galaxies away from each other and causing the expansion of the Universe to accelerate. Unlike gravity, which draws objects together, dark energy appears to drive cosmic objects apart at an increasingly rapid rate, experts say.

Edinburgh expertise

Astronomers from the School of Physics and Astronomy are leading on two of the Euclid mission’s key research areas, including analysis of data relating to so-called gravitational lensing. The phenomenon – which occurs when a galaxy causes the path of light to bend around it – produces tiny changes in the images of galaxies, which can be used to map the distribution of dark matter in space and how it has evolved over time. Edinburgh also hosts Euclid’s UK Science Data Centre, which is processing huge amounts of data generated throughout the mission for scientists to analyse worldwide. 

Professor Andy Taylor (School of Physics and Astronomy) who leads the UK’s Euclid data analysis team and the Euclid gravitational lensing data analysis, said:

This map of a large chunk of the sky is amazing, and shows Euclid's unique capacity to make high-resolution images of the Universe over such large areas. This is essential for Euclid's mission to understand dark matter and dark energy, but also provides astronomy, and the public, with an unprecedented clear view of the Universe.

Colleagues are saddened by the loss of physicist Professor Ian Shipsey, who passed away on Monday 7 October.

Members of the School of Physics & Astronomy in Edinburgh are deeply shocked and saddened by the sudden death of our colleague and friend, Professor Ian Shipsey FRS, Head of the Physics department at the University of Oxford.

Professor Shipsey had many connections with the University of Edinburgh.

After studying physics at Queen Mary in his native London, he studied for his PhD at the University of Edinburgh. His thesis title was Measurement of the two gamma decays of neutral K-mesons, using data from the NA31 experiment at CERN.

He then moved to the USA, working at Syracuse and then Purdue before returning to the UK to take up a professorship at Oxford in 2013.

Ian was a valued colleague and collaborator to many of us in Edinburgh. He had remarkable energy and a great love for physics, bringing new ideas, strong leadership and valuable advice to every situation. He understood the importance of collegiality in science, always making time for a friendly and personal conversation when we were attending the same meetings.

Ian was a member of the International Advisory Panel for the Higgs Centre in Theoretical Physics. He was an active collaborator with Edinburgh physicists and astronomers, as was a member of research collaborations including the ATLAS experiment at the LHC at CERN and the Rubin LSST project, working with the particle physics groups and Wide-Field Astronomy Unit.

Ian visited Edinburgh on several occasions over the last decade.  

Ian became profoundly deaf in his late-20s as a side effect of medical treatment and later became an early adopter of cochlear ear implants. In 2014, he presented a general interest seminar to the School on the physics and his experience with the implant, a recording of which can be found below.

Our thoughts are especially with his wife, Professor Daniela Bortoletto, also professor in physics at the University of Oxford and a collaborator with Edinburgh physicists, their daughter and family.

PhD students from 31 countries attend training in Peebles, Scotland.

The 2024 European School of High Energy Physics is taking place this autumn at Peebles, Scotland. This event brings together PhD students from across Europe and beyond to study fundamental particle physics through a series of lectures, discussion sessions and group projects.

Participants will have the opportunity to learn from world-leading experts, including Edinburgh physicists Professor Sinead Farrington and Professor Neil Turok. Dr Alan Walker will provide insights into the life and work of Professor Peter Higgs. There are also courses on science communication and outreach, with training designed to support participants in their future studies and research.

The school rotates between different host countries, and is hosted in the United Kingdom this year for the first time since 1998, taking place between 25 September and 8 October.

Organised by the European Organisation for Nuclear Research (CERN), the 2024 school is supported by a local organising committee comprised of representatives from eight UK universities and research institutes, chaired by Dr William Barter from the School of Physics and Astronomy’s Institute of Particle and Nuclear Physics. Sponsorship is provided by the School of Physics and Astronomy at the University of Edinburgh and the Science and Technology Facilities Council (STFC), enabling broader participation from students who might not otherwise be able to attend.

This year the school brings together students from 31 countries, with 47% of attendees women. 

Scientists working on the Short-Baseline Near Detector (SBND) at Fermi National Accelerator Laboratory have identified the detector’s first neutrino interactions.

Edinburgh contribution to neutrino detection

Students and post-doctoral staff at the School of Physics and Astronomy are one of the largest UK groups contributing to the experiment.

The Edinburgh team members have made significant contributions to the construction of the SBND cathode with innovative wavelength-shifting foils to enhance light collections, as well as to the understanding of the cosmic-ray tracking, photon detection and trigger systems of the detector before and after its start. Edinburgh scientists were also responsible for key items of the software infrastructure of the experiment getting it ready for the detector running.

Neutrino Detectors

The SBND collaboration has been planning, prototyping and constructing the detector for nearly a decade. The detector was built by an international collaboration of 250 physicists and engineers from Brazil, Spain, Switzerland, the United Kingdom and the United States. SBND will play a critical role in solving a decades old mystery in particle physics.

SBND is the final element that completes Fermilab’s Short-Baseline Neutrino (SBN) Program which includes the ICARUS and MicroBooNE detectors. All of the detectors are types of liquid-argon time projection chambers, and each contributes to the development of this particle detection technology for the long-baseline Deep Underground Neutrino Experiment (DUNE).

Neutrinos and the Standard Model

The Standard Model is the best theory for how the universe works at its most fundamental level. But despite being a well-tested theory, the Standard Model is incomplete. And over the past 30 years, multiple experiments have observed anomalies that may hint at the existence of a new type of neutrino.

Neutrinos are the second most abundant particle in the universe, but are difficult to study because they only interact through gravity and the weak nuclear force, meaning they hardly ever show up in a detector. Neutrinos come in three types, or flavours: muon, electron and tau. Perhaps the strangest thing about these particles is that they change among these flavours, oscillating from muon to electron to tau.

Scientists have a pretty good idea of how many of each type of neutrino should be present at different distances from a neutrino source. Yet observations from a few previous neutrino experiments disagreed with those predictions, which means there could be more than the three known neutrino flavours.

The Short Baseline Neutrino Program at Fermilab will perform searches for neutrino oscillation and look for evidence that could point to this fourth neutrino.

Beyond the hunt for new neutrinos

In addition to searching for a fourth neutrino, SBND has an exciting physics program on its own.

Because it is located so close to the neutrino beam, SBND will see 7,000 interactions per day, more neutrinos than any other detector of its kind. This large data sample will allow researchers to study neutrino interactions with unprecedented precision. The physics of these interactions is an important element of future experiments that will use liquid argon to detect neutrinos.

Whenever a neutrino collides with the nucleus of an atom, the interaction sends a spray of particles careening through the detector. Physicists need to account for all the particles produced during that interaction, both those visible and invisible, to infer the properties of the ghostly neutrinos. With the detector located so close to the particle beam, it’s possible that the collaboration could see other surprises.

One of the biggest questions the Standard Model doesn’t have an answer for is dark matter. Although SBND would only be sensitive to lightweight particles, those theoretical particles could provide a first glimpse at a ‘dark sector’.

Prof Andrzej Szelc, SBND physics co-coordinator based at the School of Physics and Astronomy said:

So far ‘direct’ dark matter searches for massive particles haven’t turned anything up. Theorists have devised a whole plethora of dark sector models of lightweight dark particles that could be produced in a neutrino beam and SBND will be able to test whether these models are true.

These neutrino signatures are only the beginning for SBND. The collaboration will continue operating the detector and analysing the many millions of neutrino interactions collected  for the next several years.