Jobs – Page 2 of 527 – CERN Courier

Antonino Zichichi 1929–2026

Antonino Zichichi, one of the most influential figures in high-energy physics and a towering presence in Italian scientific culture, passed away in Rome on 9 February 2026, at the age of 96.

Born in Trapani, Sicily, in 1929, into an ancient family from Erice, Zichichi graduated from the University of Palermo in the early 1950s. In 1955 he joined CERN, at the dawn of its experimental programme, and in 1965 he led the experiment at the Proton Synchrotron that culminated in the discovery of the antideuteron – an antinucleus composed of an antiproton and an antineutron that provided decisive confirmation of the existence of nuclear antimatter.

A professor of physics at the University of Bologna since 1960, he led the Bologna–CERN–Frascati collaboration, which carried out the first search for the tau lepton and established the experimental method through which its discovery would later be achieved at SLAC National Accelerator Laboratory. Beyond these early milestones, his results and discoveries were numerous and fundamental, including significant limits on free quark production in strong and weak interactions, the discovery of the effective energy in QCD and evidence for the first beauty baryon.

A master of invention

Equally important were his early inventions, among them the electronic circuit for time-of-flight measurements, the preshower for calorimetry and a new technology for high-precision polynomial magnetic fields. Later, by securing Italian funding for the LAA project at CERN, he launched an extensive R&D programme on innovative detection technologies. This notably allowed the development of microelectronics, which together with the design of silicon strip and pixel detectors, would become crucial for the LHC experiments and the development of the Multigap Resistive Plate Chamber (MRPC), a detector with record time resolution. The first large-scale implementation of MRPC technology was the ALICE experiment’s Time-of-Flight (TOF) system that Zichichi led for over two decades.

His scientific legacy cannot be separated from his profound and lasting contribution to the Italian National Institute for Nuclear Physics (INFN). Serving as its president from 1977 to 1982, he played a decisive role in strengthening the institute at a crucial stage of its development, consolidating its international standing and reinforcing Italy’s participation in the great global enterprises of particle physics. Under his leadership, INFN expanded its experimental commitments at CERN and in the US, while investing strategically in detector development and advanced technologies.

Zichichi was instrumental in establishing major research facilities and many large projects are tied to his name: from the LEP and LHC projects at CERN to the HERA project at DESY, and the Gran Sasso National Laboratories at INFN, that he conceived and strategically designed with its experimental halls pointing towards CERN. Today recognised as the world’s foremost underground laboratories for astroparticle physics, attracting thousands of scientists from leading institutions across the globe, the Gran Sasso National Laboratories stand as a monumental testament to Zichichi’s foresight. The idea that an international research centre such as the Gran Sasso Laboratories can serve as a crossroads for scientists from different backgrounds, cultures and institutions, collaborating in fundamental research, reflects the vision that Zichichi consistently pursued. A vision that sees science as a means of diplomacy, enabling dialogue among nations around a common goal.

Strongly convinced that scientific cooperation could be a concrete tool for diplomacy and peacebuilding, Zichichi founded the Ettore Majorana Foundation and Center for Scientific Culture in Erice, Sicily, in 1963, which became a hub for international scientific collaboration and a forum for discussion among researchers from around the world. From there, in 1982, he promoted the Erice Statement for Peace, an urgent appeal to the international scientific community to place its work in the service of peace rather than war, at a time of heightened risk of global nuclear conflict.

That same conviction informed his engagement in European and international scientific governance. Zichichi was among the founders of the European Physical Society (where he served as its president from 1978 to 1980), chaired the NATO Committee on Disarmament Technologies and represented the European Economic Community on the scientific committee of the International Science and Technology Center in Moscow. From 1986 onwards, as president of the World Lab and the World Federation of Scientists, he supported scientific development in emerging countries and focused attention on planetary emergencies.

He did not limit himself to building bridges between scientists, but also between science, culture and society. A highly skilled communicator and educator, he published widely read books and essays aimed at the broader public, and appeared frequently in the Italian media, inspiring young people across Italy and conveying to them his passion for, and belief in, the importance of scientific research. He helped shape scientific culture in Italy in the latter half of the 20th century, insisting that fundamental research is not merely a technical endeavour but a cornerstone of human progress.

Multiple honours

Over the course of his long career, Zichichi received more than 60 awards and honours in Italy and abroad, including the Knight Grand Cross of the Order of Merit of the Italian Republic and the Enrico Fermi Prize of the Italian Physical Society. He was also president of the Enrico Fermi Historical Museum and Research Centre, further testifying to his dedication to preserving and promoting Italy’s scientific heritage.

With his death, the global scientific community loses a visionary researcher, a formidable architect of international scientific collaborations, and a tireless advocate for science as a vehicle of dialogue and peace. What always struck those who shared with him the demanding and inspiring journey of research was his unfailing enthusiasm and deep passion for science, which he cultivated tirelessly until his final days. That same passion lives on not only in his discoveries and in the institutions he helped to create, but also in the generations of scientists who continue to build bridges across borders in the name of knowledge.

String pilgrimage to Santiago

**Modern methods** Researchers are converging on a common set of tools for string theory, holography and quantum gravity. Credit: IGFAE

One hundred researchers gathered in Santiago de Compostela from 21 to 23 January for Iberian Strings, the annual meeting of the vibrant Spanish and Portuguese string theory community. From the idea that black holes may test quantum gravity to the new, string-inspired ways of organising quantum field theories using symmetries and defects, the programme offered a broad overview of where string theory and holography currently sit. What stood out was the extent to which very different problems are now being tackled with a shared set of theoretical tools.

Black holes remain a clean laboratory for probing ideas about quantum gravity. Decades of work have shown they behave much like ordinary thermodynamic systems, with quantities such as temperature and entropy. A central question is how this simple large-scale behaviour arises from an underlying quantum description. Vijay Balasubramanian (University of Pennsylvania) emphasised that the challenge is not only reproducing the familiar area law – which links entropy to the area of the event horizon – but also understanding what different semiclassical calculations are really describing.

Calculations under control

One way to address this problem is to count the quantum states that give rise to a black hole’s entropy. To make progress, researchers often focus on settings where calculations are under better control. Gabriel Cardoso (IST Lisbon) discussed BPS black holes, highly symmetric solutions that allow precise calculations using holography. Stefano Trezzi (University of Barcelona) showed that near-extremal black holes, systems close to a zero-temperature limit, exhibit a universal near-horizon behaviour that provides a clean setting to study how quantum effects modify the semiclassical picture.

So much for static black holes; what about their evolution in time? Marija Tomašević (CERN) suggested that quantum effects can form a horizon where classical gravity would predict a naked singularity. Pablo A Cano (University of Murcia) and Marina David (KU Leuven) explored instead how black holes react when they are perturbed, emitting gravitational waves as they settle back to equilibrium through a process known as ringdown. Across these contributions, the focus was on separating what can be understood within controlled semiclassical calculations from what requires genuinely microscopic, quantum-gravitational input.

Some particle theories may have been gravity all along. And vice versa. These seemingly disparate worlds, with particle beams and colour confinement in one (particle physics) and curved spacetime in the other (gravity), may simply be two languages for the same physics. To translate between them, the particle side must live in one fewer dimension. Just as a hologram stores a 3D image on a 2D plate, a gravitational theory in D dimensions may be exactly equivalent to a non-gravitational quantum field theory in D–1 dimensions. This holographic correspondence is central to modern approaches to quantum gravity. The focus at the workshop was on its more applied uses, as a controlled way to learn about dynamics at strong coupling.

Elias Kiritsis (University of Crete) provided a concrete example. Using familiar spacetime physics, he studied how strongly interacting quantum systems respond to gentle deformations at low temperature, a standard probe of transport. In this setting, quantum effects can modify quantities such as the ratio of viscosity to entropy density beyond the semiclassical value.

To round the picture, Francesco Nitti (APC Paris), explored holographic models in which varying the curvature of spacetime can affect confinement, while Shota Komatsu (CERN) presented an overview of matrix-model methods in holography, emphasising how they can provide tractable descriptions of strong-coupling dynamics in specific regimes, such as large-N limits. Following ’t Hooft, theorists often treat the number of colours in an SU(N) gauge theory as a tunable parameter, providing a controlled simplification of strongly coupled dynamics.

Black holes remain a clean laboratory for probing ideas about quantum gravity

Working in simplified settings can be an effective way to make progress. In holography, a quantum field theory in two dimensions can map to a three-dimensional spacetime with a negative cosmological constant. Symmetries then constrain the gravity side, allowing us to pose – and sometimes answer – questions that would be far harder to tackle in higher dimensions or less symmetric settings. In this spirit, Stéphane Detournay (Université Libre de Bruxelles) showed how near-extremal black holes themselves can behave like two-dimensional systems, where effects due to thermodynamics, symmetry and quantum corrections can often be disentangled cleanly.

Rapid progress in understanding generalised symmetries and defects was a hot topic. Guillermo Arias-Tamargo (Imperial College London) described how recent work on non-invertible symmetries in non-linear sigma models pushes beyond the traditional picture of symmetries as simple group actions on local fields. In this modern framework, symmetries are realised through extended objects, such as defects or interfaces. Tracking how observables transform across these structures provides concrete constraints on the dynamics and phases of the theory.

A particularly sharp application came from José Calderón Infante (Caltech), who used defect-based arguments to rule out global shift symmetries in quantum gravity. Interfaces also featured prominently as physically meaningful probes, naturally connecting abstract symmetry ideas to concrete quantities such as boundary degrees of freedom and entropy-like measures – as discussed by Carlos Hoyos (Universidad de Oviedo).

The meeting covered a wide range of active topics, but controlled semiclassical arguments, low-dimensional holographic models and defect-based symmetry arguments resurfaced throughout the programme. In that sense, Iberian Strings provided an overview not only of open questions but also of modern methods.

HiLumi magnets face full-scale test

CERN has reached a crucial milestone in the advancement of the High-Luminosity Large Hadron Collider (HiLumi LHC) project with the start of the cryogenic cooldown to 1.9 K of its 95-metre-long test stand – a full-scale replica of the innovative equipment that will transform the LHC in the coming years. The test stand is designed to validate the novel magnet system (the inner triplet beam-focusing magnets) and its complex infrastructure, which is a key element in a major upgrade of the LHC that is set to enter operation in 2030.

This summer will mark the start of a four-year-long intensive work period to transform the LHC into the HiLumi LHC – a groundbreaking accelerator that will usher in a new era for high-energy physics. The HiLumi LHC will increase the number of particle collisions by a factor of 10, increasing the volume of physics data available for researchers. This leap forward will allow physicists to explore the behaviour of the Higgs boson and other elementary particles with unprecedented precision and to uncover rare new phenomena that might reveal themselves.

Exploring the unknown

“I don’t think it is possible to overstate the importance and excitement of the High-Luminosity LHC, which is the largest project undertaken by CERN for the past 20 years,” explains Mark Thomson, CERN Director-General. “Coupled with advanced new data tools and upgraded detectors, it will allow us to understand, for the first time, how the Higgs boson interacts with itself – a key measurement that will shed light on the first instants and possible fate of the universe. The HiLumi LHC will also explore uncharted territory and could reveal something completely new and unexpected. That’s the whole point of exploring the unknown: you don’t know what’s out there.”

Many of the technologies developed for the HiLumi LHC – such as superconducting crab cavities that tilt the particle beams before they collide, crystal collimators designed to remove errant particles and high-temperature superconducting electrical transfer lines to power the HiLumi magnets as efficiently as possible – have never been used in a proton accelerator before. Among these new key technologies, the inner triplet beam-focusing magnets are made of a superconducting compound based on niobium and tin (Nb₃Sn), enabling magnetic fields higher than those achieved with the current LHC niobium–titanium (NbTi) magnets (see “Superconductors for the energy frontier”). These new magnets will be deployed on both sides of the ATLAS and CMS experiments, alongside new cryogenic, powering, protection and alignment systems, and will operate at a temperature of 1.9 K, just like the LHC magnets.

The entire accelerator complex and associated experiments will benefit from the improvements

To ensure seamless integration, CERN has built, in an above-ground test hall, a full-scale test stand called the Inner Triplet String (IT String), which mirrors the underground configuration (CERN Courier March/April 2025 p8).

“All the systems have already been tested individually. The goal of the IT String is to validate their integration and their collective performance under operational conditions,” explains Oliver Brüning, CERN Director for Accelerators and Technology. “The connection and operation of all the equipment in the IT String give us a chance to optimise our procedures before the actual installation in the tunnel, so that we will be prepared and ready for an efficient and smooth installation.”

Harnessing potential

The large LHC experiments ATLAS and CMS will also undergo a major upgrade to enable them to harness the full scientific potential of the HiLumi LHC collisions – work that is being carried out in close coordination with hundreds of institutes worldwide. Additionally, the entire accelerator complex and associated experiments will benefit from improvements, says the lab, solidifying CERN’s leadership in high-energy physics.

The cooldown of the HiLumi LHC test string, which is achieved using a liquid-helium refrigeration and distribution system, is expected to take several weeks to complete.

Physics labs under the lens

Physics is beautiful in its ideas and in the people who pursue them across borders. What better, then, than for 16 laboratories across Asia, Europe and North America to throw open their doors for a photography competition, allowing the aesthetically inclined to immortalise on film the wonders within. The votes are now in.

The winning image of the 2025 Global Physics Photowalk, by photographer Marco Donghia, shows INFN National Laboratories of Frascati researcher Raffaella Donghia seated beside an open cryostat during installation of an ultracold experiment at COLD, the CryOgenic Laboratory for Detectors (see “First place” image). The apparatus houses an axion haloscope – a cryogenic antenna consisting of a microwave cavity resonating at about 9 GHz, immersed in a powerful 9 tesla magnetic field and connected to an ultra-low-noise amplification system designed to search for ultralight dark-matter candidates such as axions or dark photons (CERN Courier January/February 2026 p21). If ultralight dark matter circulates in a galactic halo, it could excite the resonant cavity at a frequency corresponding to the particle’s mass, appearing as a minute increase in electromagnetic power at that frequency. Cooling the system to 10 mK suppresses thermal noise to the point that quantum noise dominates.

“The image stood out for its clear visual storytelling and masterful use of light, which leads the eye through the scene and emphasises the moment of discovery,” said judge Tabea Rauscher, then creative lead at the European Molecular Biology Laboratory. “The researcher appears small in relation to the cryostat, highlighting the scale of the technology while keeping the human presence at the centre. The lighting creates a quiet, almost cinematic atmosphere that captures both the intensity and the solitude of scientific work.”

The photographs move between abstraction and lived experience

Fellow judge Dmitri Denisov, deputy associate laboratory director for high-energy physics at Brookhaven National Laboratory in the US, noted that while the judges chose Donghia’s photograph for its ability to convey the “deep connection between the apparatuses used in particle physics and the human developing them,” the second- and third-place photographs were chosen for their “deep looks into the inner workings of experiments and impressive display of colours.”

The judges awarded second place to Matteo Monzali for his photograph of a nuclear-physics experiment at INFN National Laboratories of Legnaro in Italy (see “Runner up” image) and third place to Hugo Pardinilla for a close-up image of a photomultiplier from the KM3NeT/ORCA experiment, a neutrino telescope currently being installed in the Mediterranean Sea at a depth of 2500 metres off the coast of Provence, France (see “Third place” image). Members of the public awarded first and second place to Yannig Van De Wouwer’s photographs of GANIL, the heavy-ion accelerator in Caen, France, featuring pipes and cables serving the SPIRAL2 linear accelerator and iridescent patterns in a beam pipe (see “Public preference” image). The public’s third choice went to Monzali’s snap of the AGATA–PRISMA setup in INFN Legnaro.

Deeply human

“Serving as a judge for the 2025 Global Physics Photowalk, I was struck by the range and sensitivity of the submissions,” concludes judge Will Warasila, a freelance photographer for the New York Times. “The photographs move between abstraction and lived experience – finding form, rhythm and quiet beauty in scientific spaces, while foregrounding the people whose labour and curiosity make this work possible. Across geographies and institutions, these images show how photography can slow us down, make complex systems legible and remind us that science is not only technical, but deeply human.”

The Global Physics Photowalk is organised by the Interactions Collaboration (interactions.org), an international network of particle-physics institutions including CERN and over 20 partner laboratories and research infrastructures around the world.

When accelerators turn into sweaters

**Accelerator materiality** Knitted from copper wire, the piece *When Accelerators Turn into Sweaters*, by artist Julijonas Urbonas, reduces accelerator infrastructure to garment scale. Credit: J Urbonas

What happens when an artist enters a particle-physics laboratory, not to explain its discoveries or visualise its equations, but simply to remain, observe and respond? In the Spaces Between, a sustained reflection on the long-running Arts at CERN programme, argues that what emerges is not illustration or explanation, but a shared space of inquiry – one that works with uncertainty rather than resolving it, echoing the statistical, instrument-mediated nature of contemporary physics.

Both art and particle physics push at the edges of what can be known, imagined and expressed. Through its programmes, Arts at CERN hosts artists for extended residencies at the laboratory, where they meet physicists and engineers, attend seminars, visit experimental sites and engage directly with ongoing research. The artists are not tasked with illustrating experiments or communicating results. Instead, they develop independent works – installations, performances, films, sculptures – shaped by sustained dialogue with the scientific community.

Creating coalitions

Edited by Mónica Bello, former head of Arts at CERN (CERN Courier March/April 2025 p41), the book brings together essays, images and reflective texts by artists, scientists and collaborators involved in the artist residency programme. Rather than presenting a catalogue of finished works, it focuses on the conditions that make exchange possible: how artists encounter scientific infrastructures, and how meaning begins to form in spaces where neither discipline fully sets the rules.

The book is organised around four broad themes: “quantum”, cosmology, experimentation and the unknown. These function less as explanatory frameworks than as loose points of orientation, allowing contributions to remain fragmentary and open-ended. The structure mirrors the reality of interdisciplinary work, which rarely unfolds in clean, linear ways, but instead through moments of partial understanding, misalignment and return.

For readers trained in physics, this approach may feel unexpectedly familiar. Scientific knowledge rarely emerges fully formed; it develops through iteration, uncertainty and interpretation. In a similar spirit, the contributions resist tidy conclusions and treat concepts not as definitions to be settled, but as materials for creative reworking. What matters is less resolution than the act of thinking itself, an openness that mirrors the exploratory character of research. At times this displacement can feel destabilising, yet it is precisely this imaginative expansion that gives the book much of its intellectual force.

This sensibility is vividly captured in Rohini Devasher’s Beyond the Standard Model. Spread across a dark, planetary surface, words such as “uncertainty”, “duality”, “observer”, “wonder” and “serendipity” – form a dense, drifting constellation. Some terms carry clear scientific weight; others belong to the emotional and imaginative registers that accompany research but rarely appear in formal papers. For Devasher, the interest lies precisely in language. By placing these words on the same visual plane, the piece loosens disciplinary hierarchies and allows concepts to float, cluster and collide. As the artist notes, the words are intended to read as a web. Rather than explaining physics, it evokes the conceptual environment in which physics thinking takes place.

Places and perspectives

On another page, language again becomes material in Cecilia Vicuña’s Ceque. The work draws on the ceq’e system of the Inca civilisation: a network of conceptual and ceremonial lines radiating outward from the city of Cusco, that are used to organise ritual practice, social relations and cosmological understanding. Rather than functioning as fixed geometrical paths, ceq’es describe relationships between places, perspectives and moments in time.

The page opens with the line “The ceq’e is not a line, it is an instant, a gaze.” Around it, words tilt, scatter and spiral – “a thought, radiating”, “another meridian”, “seen from above or from below”. Reading becomes a spatial act rather than a linear one. Meaning is not extracted or fixed; it unfolds uneasily alongside the order, diagrammatic structures through which Western science typically organises knowledge. The book offers little explicit explanation of the concept, allowing the work instead to function as an alternative way of organising knowledge: relational, situated and resistant to a single point of view.

Visual thinking also surfaces in drawings from Suzanne Treister’s project The Holographic Universe Theory of Art History (THUTOAH), including Alessandra Gnecchi’s Holographic Universe Principle. The work resembles a hand-drawn cosmology sketched in coloured pencil: strings, branes and horizons coexist with handwritten annotations and looping arrows. The emphasis is not on polished representation, but on the labour of thinking – the scribbles, approximations and half-formed connections that precede formalisation. Theory appears not as a final statement, but as something constantly under construction.

In the Spaces Between — Credit: dpr-barcelona

One of the more quietly striking works in the book is Julijonas Urbonas’s When Accelerators Turn into Sweaters: a translucent garment constructed from fine copper-stabilised superconducting fibres (see “Accelerator materiality” image). The title collapses the scale of accelerator infrastructure into a wearable object, shifting attention from machines as abstract systems to the materials from which they are built. As Urbonas puts it, the work aims to “bring a monumental, sealed infrastructure into the scale of the body, not just visually, but physically and imaginatively… a translation from the remote language of high-energy physics into something you can almost inhabit.”

In doing so, it foregrounds the material reality of high-energy physics – copper as thread and cable at once. Though made of copper, the sweater evokes the magnetic levitation of the Meissner effect, a reference to the cryogenic superconductivity of the LHC. As Urbonas observes, “the accelerator needs extreme cold to do its job, while a sweater’s whole purpose is warmth.” By keeping that gap open, the piece operates less as demonstration than as speculation: a domestic object positioned against an environment colder than outer space, inviting viewers to rethink how scientific infrastructure is imagined. Urbonas leaves the reader with a provocation: “What if physicists talked in the knitwork of the world instead?”

For accelerator physicists, this change of scale may register not simply as metaphor, but as a reminder that even the largest facilities depend on materials physically assembled, connected and maintained by hand. By reframing accelerator infrastructure at human scale, the piece foregrounds construction and material composition rather than the monumental image of the machine, aligning with the book’s broader emphasis on process over spectacle.

The contributions make clear that Arts at CERN is not a peripheral outreach activity, but a mature programme of sustained exchange

In the Spaces Between does not romanticise interdisciplinarity as a seamless merging of perspectives or a frictionless dialogue between equals. Several contributors openly acknowledge the asymmetries between artistic and scientific practice within a large research institution, where scientific priorities and infrastructures inevitably set the operating conditions. Rather than glossing over these tensions, the book treats them as productive constraints that actively shape how collaboration unfolds.

Taken together, the contributions make clear that Arts at CERN is a mature programme of sustained exchange. Its longevity has not led to conceptual closure; instead, the dialogue has deepened while remaining exploratory, evolving rather than resolving.

With its emphasis on process rather than outcomes, the book offers a rare window into how artistic inquiry operates inside a laboratory environment. It does not try to merge art and science, nor to reduce one to the language of the other. Instead, it traces the intellectual and imaginative terrain that lies between them, a space defined not by synthesis, but by ongoing negotiation.

Ultimately, In the Spaces Between suggests that experimentation runs deeply through both artistic and scientific practice, not only as a set of methods for testing ideas, but as a shared commitment to iteration, risk and revision. The sustained dialogue documented here does not aim at synthesis or resolution; rather, it creates conditions in which new forms of knowledge can emerge, forms that remain open-ended. The book will be of particular interest to those working at the intersections of art, science and research institutions, and to readers interested in what happens when disciplines meet without being forced into premature coherence.

Michele Parrinello Award honours innovation in computational physical science

In honour of Italian physicist professor Michele Parrinello, open-access publisher MDPI has launched the Michele Parrinello Award – a biennial award recognising senior academics in computational physical science. As the deadline for 2026 nominations approaches, we reflect on professor Parrinello’s remarkable career and enduring legacy.

Professor Michele Parrinello

Interview with Prof. Michele Parrinello: Pioneer in Computational Science

Known for his innovative approach to computational science, professor Parrinello’s role in the development of the Car–Parrinello method (with Roberto Car) remains one of his most influential contributions to molecular dynamics. He is similarly celebrated for his role in co-developing the Parrinello–Rahman method, alongside his recent work in metadynamics.

Testament to his global influence, professor Parrinello has received several accolades, such as the Rahman Prize, the Dirac Medal and the Erwin Schrödinger Institute for Mathematics and Physics Medal. He is also a member of several academies and learned societies, including the German Berlin-Brandenburgische Akademie der Wissenschaften, the British Royal Society and the Italian Accademia Nazionale dei Lincei.

Reflecting on his advice to young researchers, professor Parrinello says that they should not fear new ideas. He has observed that many early-career scientists hesitate to go against the mainstream, often worrying about potential consequences. Instead, he encourages them to remain confident in the value and meaning of their work, and to avoid being overly influenced by the opinions of others.

Through the Michele Parrinello Award, it is hoped that professor Parrinello’s remarkable legacy will inspire future generations to pursue excellence in their fields.

The full interview with professor Parrinello is available online.

The Michele Parrinello Award

Michele Parrinello’s work has been characterised by its interdisciplinary impact. Accordingly, the award welcomes nominees from a range of related fields, including physics, chemistry and materials science.

Nominations will close on 31 March 2026, with the winner announced on 31 July 2026. The awardee will receive a monetary prize of EUR 50,000, alongside a commemorative medal and a certificate.

For more information about the nomination process, visit the award homepage.

2025 Award Committee

Interview with Prof. Xin-Gao Gong: Chair of the Michele Parrinello Award Committee

The Michele Parrinello Award Committee is chaired by professor Xin-Gao Gong. Professor Gong studied with professor Parrinello in Italy during his early career. As an academician of the Chinese Academy of Sciences and a professor at Fudan University in China, he focuses his research on computational physical sciences and condensed-matter physics.

Much like how professor Parrinello inspired his early career, professor Gong hopes that “The Michele Parrinello Award will recognise scientists who have made significant contributions to the field of computational condensed-matter physics and at the same time set a benchmark for the younger generation, providing clear direction for their pursuit.”

Watch the full interview with professor Xin-Gao Gong online.

MDPI champions outstanding research

Recognising the exceptional work of academics lies at the heart of MDPI’s mission to foster open scientific exchange, and is reflected in its extensive awards programme.

The MDPI Sustainability Foundation furthers this mission through its commitment to advancing sustainable development, advocating for scientific progress and global collaboration.

Alongside the Michele Parrinello Award, the foundation oversees the World Sustainability Award, the Emerging Sustainability Leader Award and the Tu Youyou Award.

The most elusive higgsinos

ATLAS figure 1 — **Fig. 1.** Observed and expected limits at 95% CL for 1ℓ1T (purple) and displaced track (red) searches are shown in the chargino-neutralino mass difference versus chargino mass plane, along with previous limits from the LEP2 (grey) and ATLAS (blue, light green and orange) experiments. Credit: ATLAS Collab., adapted from arXiv:2511.20042

Supersymmetry has so far eluded discovery at the LHC, yet it retains strong theoretical appeal as an extension of the Standard Model (SM), and potential hiding places remain. In two recent analyses, the ATLAS collaboration sets new bounds on compressed higgsino models, where the proposed particles lie very close in mass. The collaboration used machine-learning techniques to target some of the most elusive signatures at the LHC: low-momentum decay products.

Without extreme fine tuning, quantum corrections would drive the Higgs-boson mass far above the electroweak scale. Supersymmetry prevents this by introducing fermion partners for the SM bosons (and vice versa) so that their quantum contributions naturally cancel. The result is a partner for every SM particle – including higgsinos, the fermionic counterparts of the Higgs field. Higgsinos mix with the partners of the electroweak gauge bosons to form electrically neutral and charged states known as neutralinos (χ̃⁰) and charginos (χ̃^±). The lightest neutralino (χ̃⁰₁) is stable in a wide class of models and may naturally account for the observed dark-matter abundance.

In compressed scenarios, the tiny mass-splitting between these new particles poses a distinct experimental challenge. When a heavier state decays to χ̃⁰₁, the small mass difference leaves little energy for the accompanying SM particles. The visible decay products therefore carry very low momentum and may fall below reconstruction and identification thresholds. The new analyses focus precisely on this regime using the full Run 2 dataset collected at √s = 13 TeV, with two complementary strategies optimised for different values of the mass splitting.

Firstly, a “displaced track” search targets scenarios with a mass difference between the lightest chargino χ̃^±₁ and χ̃⁰₁ of 0.3 to 1 GeV, in which the χ̃^±₁ has a non-negligible lifetime and can travel a few millimetres before decaying into an invisible χ̃⁰₁ and a low-momentum charged pion. The resulting event signature is a pion track with a large transverse impact parameter and high missing transverse momentum from the neutralinos. Significant improvement in signal sensitivity is achieved by the use of two dedicated neural networks (NNs), where one exploits the global event kinematics and the other focuses on the displaced track characteristics.

A “one-lepton-one-track (1ℓ1T)” search instead targets scenarios with a larger mass splitting of 1 to 3 GeV, in which the heavier neutralino χ̃⁰₂ promptly decays into the χ̃⁰₁ and two low-momentum leptons. Since these could elude the existing ATLAS identification techniques, dedicated low-momentum electron and muon identification algorithms have been developed using NNs that exploit track and calorimeter information. The new algorithms are applied to leptons with momentum as low as 0.5 GeV for electrons and 1 GeV for muons, below the standard reconstruction thresholds, resulting in a signature consisting of one lepton and one lepton-like track. An additional NN enhances sensitivity for event classification, exploiting kinematic features that depend strongly on the mass splitting.

The observed data are consistent with the SM predictions, with no signs of new physics emerging in the targeted phase-space. Based on this result, lower limits on the higgsino masses are set at 95% confidence level (CL) (see figure 1). The 1ℓ1T search excludes a mass-splitting region between 0.8 and 2.0 GeV, extending previous limits from the LEP experiments up to a maximum χ̃^±₁ mass of 132 GeV for a 1.8 GeV mass splitting. The displaced track search extends the exclusion limits previously set by the ATLAS experiment by about 30 GeV, reaching a χ̃^±₁ mass of 199 GeV for a 0.6 GeV mass splitting. Together, the two searches exclude χ̃^±₁ masses below 126 GeV at 95% CL over the targeted mass splitting range. Limits set by the ATLAS collaboration now supersede those from the LEP experiments in all mass-splitting ranges.

With this result, ATLAS is now able to set limits over the full range of higgsino mass splittings that are interesting for naturalness, marking a significant milestone in the search for supersymmetry. The new Run 3 dataset, along with advanced analysis techniques, will push these searches even further – perhaps towards the discovery of physics beyond the SM.

ICABU fishes for accelerator innovations in Pohang

The 27th International Conference on Accelerators and Beam Utilizations (ICABU2025) attracted 300 experts to Pohang, South Korea, from 12 to 14 November 2025. Once a small fishing village, Pohang has developed into a major research hub and now hosts more than 22 R&D institutions. These include Pohang University of Science and Technology (POSTECH), the Pohang Accelerator Laboratory – home to the 3 GeV PLS-II synchrotron radiation source and PAL-XFEL hard X-ray free-electron laser – and the Asia-Pacific Center for Theoretical Physics. ICABU itself began in 1997 as the International Proton Accelerator Workshop, hosted by the Korea Atomic Energy Research Institute. Since 2009, it has grown into an international conference.

Particle beams are becoming increasingly important to materials engineering. Yunseok Kim (Sungkyunkwan University) discussed how helium-ion irradiation can be used to manipulate hafnium oxide, a material widely employed as an insulating layer in modern microelectronics. In very thin films, hafnium oxide can sustain a switchable electric polarisation that allows information to be stored, known as ferroelectricity. Yet, this state is normally fragile. Kim showed that controlled irradiation with low-energy helium ions can introduce and rearrange atomic-scale defects in the crystal lattice, stabilising the polarised state.

The meeting also addressed applications in nuclear medicine. A team from the Institute for Rare Isotope Science (IRIS) reported progress towards a domestic production route for the therapeutic alpha-emitter actinium-225, based on irradiation of thorium-232 targets with 50–70 MeV protons. Actinium-225 is both expensive and scarce, with current clinical use relying heavily on imports. Even an initial domestic supply would improve clinical availability and support the wider adoption of targeted alpha therapies.

Alongside applications, there was also a focus on progress in accelerator hardware itself

Alongside applications, contributions also focused on progress in accelerator hardware itself. Garam Hahn (PAL) and collaborators reported on a compact 5 T magnet system based on high-temperature superconductors (see p30). Operating without liquid cryogens, it is designed to shift the wavelength of synchrotron radiation, since stronger magnetic fields force tighter beam curvature and raise the characteristic photon energy. The system drew substantial attention from the accelerator-technology community, as it has the potential to increase high-energy photon brilliance by many orders of magnitude.

Beyond technical developments, ICABU2025 also addressed the evolving policy landscape for large-scale research infrastructure. In South Korea, the Korea Large Accelerator Act was recently established to manage, support and govern large accelerator facilities. Dongsoo Jang, deputy director of the Ministry of Science and ICT (MSIT), outlined strategies aimed at improving coordination, access and long-term planning across the country’s accelerator infrastructure.

Next year, the event will be hosted by the Korea Multi-purpose Accelerator Complex (KOMAC) and held in Gyeongju. Often described as a “museum without walls,” Gyeongju is one of Korea’s most historic cities and a symbol of cultural diplomacy, aligning well with the spirit of ICABU.

Suppression grows with system size

CMS figure 1 — **Fig. 1.** Charged-particle nuclear modification factor R_AA in oxygen–oxygen, neon–neon, xenon–xenon and lead–lead collisions at the LHC. R_AA is shown as a function of the cube root of the nucleon number A, which is proportional to the nuclear radius. Credit: CMS Collab. 2026 arXiv:2602.21325

When atomic nuclei collide at the LHC, they produce tiny droplets of quark–gluon plasma (QGP) and energetic partons plough through it, slowing down in the process. In a new analysis, the CMS collaboration compared high transverse momentum (p_T) particle yields in oxygen–oxygen, neon–neon, xenon–xenon and lead–lead collisions, with the nucleon numbers of the colliding particles increasing in the sequence 16 < 20 < 129 < 208. The results suggest a steady growth of parton energy loss with the size of the colliding system.

High-p_T particles come from the fragmentation of quarks and gluons produced in the earliest hard scatterings of a collision. As these partons cross the QGP, they interact with the medium and radiate, losing energy in the process. This is one of the clearest signatures of QGP formation. How much energy partons lose depends on how far they travel inside the medium, which in turn grows with the size of the colliding nuclei. Although firmly established in xenon–xenon and lead–lead collisions, the precise way this quenching depends on the path length is not yet fully understood.

Light-ion collisions provide a controlled way to vary the system size and isolate this path-length dependence. In July 2025, the LHC delivered its first ever oxygen–oxygen and neon–neon collisions (CERN Courier November/December 2025 p8). The CMS collaboration analysed the data from this dedicated one-week run to perform a systematic study of high-p_Tcharged-particle suppression across multiple collision systems.

The analysis combines existing measurements in oxygen–oxygen, xenon–xenon and lead–lead collisions with the first measurement of the charged-particle nuclear modification factor, R_AA, in neon–neon collisions at a centre-of-mass energy of 5.36 TeV per nucleon pair. The observable R_AA quantifies how particle yields deviate from expectations based on proton–proton collisions. The four systems were analysed using identical p_T-intervals, enabling a consistent comparison across systems.

The results should help inform the choice of ion species

For smaller nuclei, such as oxygen and neon, many experimental uncertainties shared with the proton–proton reference largely cancel, for example, those related to tracking. This leads to particularly precise measurements of R_AA across a wide p_T range, which is difficult to achieve in larger systems. Combined with the wide span of nuclear sizes, this precision enables a more direct assessment of how parton energy loss depends on in-medium path length.

For a fixed transverse momentum interval, the suppression increases smoothly with system size, from light to heavy ion collisions (see figure 1). Conversely, for a given nuclear system, the suppression is stronger at lower transverse momenta and progressively weakens as it increases. Expressed in terms of the cube root of the nucleon number, which is proportional to the nuclear radius, the results follow a simple ordering with the size of the system, offering a natural framework to test the evolution of energy loss with system size.

The data indicate that nuclear suppression develops gradually as the nuclear system grows, consistent with a picture in which partons interact with QGP droplets whose extent and density evolve smoothly across collision systems. Calculations that omit energy loss show little variation with system size and do not describe the observed suppression, whereas models that include it qualitatively reproduce the observed trend within uncertainties. The data, presented this way, offer a guide for further improvements on their A-dependence.

This study places new quantitative constraints on parton-energy-loss mechanisms and on the emergence of QGP-like behaviour in small nuclear systems. The results should help guide future theoretical developments and inform the choice of ion species in upcoming heavy-ion studies at the LHC.

Quarkonium experts regroup at CERN

**Internal structure** The 17th Quarkonium Working Group attracted more than 200 researchers to CERN. Credit: N Brambilla

Quarkonium physics dates back to the November Revolution of 1974 and the discovery of the J/ψ, a bound state of a charm quark and its antiquark; this was soon followed by the excited ψ(2S) state and its bottom–antibottom analogue ϒ(1S) (CERN Courier September/October 2025 p35). These non-relativistic systems hold a unique place in QCD, encompassing a precise hierarchy of characteristic energy scales. Some, such as heavy-quark masses, are amenable to perturbative treatment, while others, such as the confinement scale, are inherently non-perturbative. To capture this interplay systematically, effective field theories such as non-relativistic quantum chromodynamics (NRQCD) were developed from the 1990s onwards.

The quest to interpret quarkonium phenomena within this unified framework, combined with an explosion of experimental results from B factories and hadron colliders, sparked the creation of the Quarkonium Working Group (QWG) Workshop in 2002. Now organised roughly every 18 months at research institutions around the world, the workshop has become a regular meeting point for the quarkonium community. The 17th QWG brought together more than 200 researchers at CERN from 17 to 21 November.

Renaissance

The first part of the workshop naturally reflected this historical and conceptual foundation, focusing on spectroscopy and decays. In recent years, quarkonium spectroscopy has become a driver of new discoveries in QCD. A prime example is the so-called charmonium renaissance, marked by the observation of several exotic states – including the χ_c1(3872), T_cc+(3875) and charged Z_c states. These “XYZ” states can’t be interpreted as conventional charmonia and their internal structure remains under active investigation both at the experimental and theoretical levels (CERN Courier November/December 2024 p33).

Experimental talks in the opening sessions reported on searches for exotic hadrons and their decay channels. Dmytro Meleshko (Giessen University) from the Belle II collaboration reported on excited bottomonium states, placing particular emphasis on the ongoing analysis of the ϒ(10753) resonance, and the experimental signatures that can distinguish between a tetraquark, a hybrid and a S–D mixed bottomonium state. Ilya Segal (Bochum University) presented recent results by the LHCb collaboration on the radiative decay χ_c1(3872) → ψ(2S)γ. Yue Xu (University of Washington) illustrated an analysis for fully-charmed tetraquarks in the J/ψ–ψ(2S) channel by the ATLAS collaboration, confirming the X(6900) resonance with high significance.

On the theory side, Abhishek Mohapatra (TUM) described ongoing efforts to extend effective-field-theory methods originally developed for quarkonium to more complex exotic systems using the Born–Oppenheimer (BOEFT) approach, which takes lattice QCD inputs to address the QCD non-perturbative dynamics without assuming a specific internal structure for the exotic states.

The third day turned to production. Some NRQCD calculations predict negative production rates for J/ψ and χ_c mesons at high transverse momentum, a clearly unphysical result. Hee Sok Chung (Gangneung-Wonju National University) highlighted how this problem can be addressed by improving the formal treatment of emissions near the production threshold. New production measurements for J/ψ and ψ(2S) from the CMS and ALICE collaborations were presented, alongside new calculations for the production of the χ_c1(3872) and of the pentaquarks P_cc(4312) and P_cc(4457).

The field’s rapid evolution makes the time ripe for a third, comprehensive QWG document

The programme then broadened to Standard Model applications, where quarkonium observables can constrain fundamental QCD parameters such as the strong coupling constant and gluelump masses – the gluonic mass contribution in quarkonium hybrid states, as obtained from lattice QCD. Laurids Jeppe (DESY) from the CMS collaboration discussed the enhancement observed around the top–antitop threshold in the invariant mass spectrum, first measured by CMS and later confirmed by ATLAS (CERN Courier September/October 2025 p9). In a round-table discussion, participants debated the signal’s interpretation in terms of a quasi-bound top–antitop meson or a possible new-physics origin, with both scenarios allowed by the current level of experimental precision, and with the main uncertainties coming from the background modelling. The workshop closed with sessions on quarkonium in media, featuring recent progress in calculating quarkonium transport coefficients from both lattice QCD and perturbation theory.

Progress and puzzles

The discussions across previous QWG workshops crystallised into two foundational documents named “Heavy quarkonium physics” and “Heavy quarkonium: progress, puzzles, and opportunities”, that have since trained generations of young physicists and stand as key references for the community. The field’s rapid evolution makes the time ripe for a third, comprehensive QWG document to capture the wide range of new and enduring topics that currently define it, including the BOEFT framework as a tool to achieve a unified description of all XYZ exotic states, studies of non-equilibrium quarkonium evolution in the QCD medium, informed by new data from the CBM experiment, and the recent development of new automated event generators for quarkonium production.

The next workshop will take place in spring 2027.

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