Discussions in June 2025 at the Open Symposium of the European Strategy for Particle Physics demonstrate strong progress towards ensuring that CERN remains a world leader in collider physics and technology Venice, Italy, 27th June 2025. This week, more than 600 scientists met in Venice, Italy, to debate the future direction of European particle physics in the global context. The Open Symposium is an important step in the ongoing update of the European Strategy for Particle Physics (ESPP), providing particle physicists in Europe and beyond with an opportunity to assess scientific priorities and technological approaches for the medium- and long-term future.  The Strategy recommendations, which will reflect the ambitions and priorities of the community, are expected to be submitted to the CERN Council in early 2026. Projects are approved by the Council through a separate decision-making process, taking the Strategy recommendations and other considerations into account. The previous ESPP update in 2020 emphasised the importance of ensuring Europe’s continued scientific and technological leadership. Building on the discovery of the Higgs boson at CERN’s Large Hadron Collider (LHC), it recommended an electron-positron “Higgs factory” as the highest-priority next facility after the LHC reaches the end of its operational lifetime in 2041 and that Europe should have the long-term ambition to operate a proton-proton collider at the highest achievable energies. “The time is ripe to forge a brilliant future for our field in Europe, together with our global partners,” said Fabiola Gianotti, CERN Director-General. “The worldwide CERN community’s achievements in implementing the 2020 ESPP update prove that we are a strong community, capable of designing, building and operating facilities of astounding complexity that consistently exceed expectations. This is our greatest asset as we prepare for even more ambitious projects.” A total of 266 submissions from the community, spanning all aspects of particle physics, formed the basis for vibrant discussions during the week-long Open Symposium. Participants from almost 40 countries, including many early-career researchers, expressed the need for an ambitious and innovative research programme that will maintain CERN as a world-leading centre for collider physics while also ensuring a diverse programme that maximises physics reach and includes approaches complementary to colliders. Contributions from researchers in neighbouring fields also demonstrated the rich connections between particle physics and nuclear and astroparticle physics. Identifying the most promising flagship collider to succeed the LHC at CERN is a central aim of the 2026 ESPP update. In direct response to the 2020 Strategy update, a feasibility study for a Future Circular Collider (FCC) facility that could host a 91 km-circumference electron-positron collider followed by an energy-frontier proton-proton collider in the same tunnel was conducted, and the report was released in March 2025. In addition to the FCC, other projects under consideration in the relevant time frame are an electron-positron linear collider at CERN and smaller colliders that would re-use the LHC tunnel. Great progress has also been made towards a muon collider, but several years of R&D work are still needed to demonstrate its feasibility. National input from members of the high-energy physics communities in CERN’s 25 Member States so far indicate broad support for the FCC programme on account of its outstanding scientific potential and long-term strategic value. Underscoring the importance of continued dialogue and assessment, discussions on alternative options will continue. Several important steps remain before the ESPP recommendations are finalised. Expert ESPP panels are working on a comparative evaluation of proposed future colliders in terms of their physics potential, environmental impact and sustainability, technical maturity, cost, required human resources and implementation timelines. “I am happy to see that the recommendations of the 2020 ESPP update and their implementation via the FCC Feasibility Study enjoy overwhelming support from the vast majority of the high-energy physics community as well as leading experts,” said Costas Fountas, President of the CERN Council. “The discovery of the Higgs boson at the LHC in 2012 marked the start of a new journey of discovery that can only be realised by a future collider with the broadest and most powerful research programme, and the CERN Council eagerly awaits the community’s final recommendations.” The ESPP conclusions are eagerly awaited, as delays in reaching agreement on which collider should follow the LHC are viewed by the community as a risk to CERN’s leadership and its potential to attract interest from scientists across the world. Following rich dialogue at the Open Symposium, discussions will continue in the coming months. Together with a second round of input from the national communities, which is to be submitted by 14 November, they will provide the basis for the final Strategy recommendations to be drafted in December.  “I am pleased to see so many colleagues from Europe and beyond participating actively in debating the scientific input received from the particle physics community in order to define the next large accelerator project that will allow CERN and Europe to maintain their leading role in our field,” said Karl Jakobs, Strategy Secretary. “In addition, the scientific goals and priorities in other areas of physics were discussed. We anticipate further rich input and discussion as the 2026 ESPP update enters its final strait.” Image: Artistic view of a possible Future Circular Collider and of a particle collisionCredit: PIXELRISE and CERN

Author: Michael Gregory In September and October 2025, the European Physical Society is running a weekly webinar series on Discovery Space. The first webinars are aimed primarily at teachers who are new to Discovery Space, and will support teachers to implement Discovery Space learning scenarios in their classroom. In October, the focus will shift towards a deeper understanding of Discovery Space, how to spread its use amongst colleagues and become ambassadors for the project. Hosted by EPS project officer Michael Gregory, and joined by exciting guest hosts from across Europe, each webinar will focus on a different learning scenario or aspect of Discovery Space. September Schedule Date/Time Title Hosts Registration Link Tues Sept 9th 17:00 –   18:00 CET Introduction to Discovery Space and online Platform Nikolaos Grammatikos and Evangelia Anagnostopoulou Institute of Communication and Computer Systems (Greece) https://forms.office.com/e/Z5xLzN4pXd Tues Sept 16th 17:00 –   18:00 CET AI-Enhanced Pendulum Learning Scenario Dimitris Koulentianos, Ellinogermaniki Agogi (Greece)   https://forms.office.com/e/Zj3Bh18guW Mon Sept 22th 18:00 –    19:00 CET Zookeepers of the Galaxy Learning Scenario Michael Gregory European Physical Society https://forms.office.com/e/SNff1mMCJh October Schedule https://eps.org/event/discovery-space-fall-webinar-series/ This webinar series follows the success of our “Spring into Discovery Space” webinar series last April and May,  Recordings of the webinars are published in a playlist on the EPS YouTube channel: Spring Into Discovery Space Playlist. Discovery Space is an EU-funded project to develop an Exploratory Learning Environment to facilitate students’ inquiry and problem-solving through learning scenarios featuring virtual and remote labs. Students are guided through differentiated learning pathways, customized by their input as they progress through learning scenarios covering a variety of topics.  For more information on Discovery Space, please see: https://discoveryspace.eu/.

Demonstration of first antimatter quantum bit paves the way for substantially improved tests of nature’s fundamental symmetries Geneva, 23th July 2025. In a breakthrough for antimatter research, the BASE collaboration at CERN has kept an antiproton – the antimatter counterpart of a proton – oscillating smoothly between two different quantum states for almost a minute while trapped. The achievement, reported in a paper published today in the journal Nature, marks the first demonstration of an antimatter quantum bit, or qubit,­ and paves the way for substantially improved comparisons between the behaviour of matter and antimatter. Particles such as the antiproton, which has the same mass but opposite electrical charge to a proton, behave like miniature bar magnets that can “point” in one of two directions depending on their underlying quantum mechanical spin. Measuring the way these so-called magnetic moments flip, using a technique called coherent quantum transition spectroscopy, is a powerful tool in quantum sensing and information processing. It also enables high-precision tests of the fundamental laws of nature, including charge-parity-time symmetry. This symmetry rules that matter and antimatter behave identically, which is at odds with the observation that matter vastly outweighs antimatter in the Universe. Particles have quantum characteristics that defy our common sense, such as the characteristic of interfering with themselves, as demonstrated in the double slit experiment. Interactions with the surrounding environment can quickly suppress these interference effects through a process known as quantum decoherence. Preserving coherence is essential for controlling and tracking the evolution of quantum systems, like the transitions between the spin states of a single antiproton. Although coherent quantum transitions have been observed before in large collections of particles and in trapped ions, they have never been seen for a single free nuclear magnetic moment – despite the latter featuring prominently in physics textbooks. The BASE collaboration has now achieved this at CERN’s antimatter factory.  In some respects, the feat can be likened to pushing a child on a playground swing. With the right push, the swing arcs back and forth in a perfect rhythm. Now imagine that the swing is a single trapped antiproton oscillating between its spin “up” and “down” states in a smooth, controlled rhythm. The BASE collaboration has achieved this using a sophisticated system of electromagnetic traps to give an antiproton the right “push” at the right time. And since this swing has quantum properties, the antimatter spin-qubit can even point in different directions at the same time when unobserved. The BASE experiment studies antiprotons produced at CERN’s antimatter factory by storing them in electromagnetic Penning traps and feeding them one by one into a second multi-trap system to, among other things, measure and change their spin states. Using this set-up, the BASE collaboration has previously been able to show that the magnitudes of the magnetic moments of the proton and antiproton are identical within a just few parts-per-billion. Any slight difference in their magnitudes would break charge-parity-time symmetry and point to new physics beyond the Standard Model of particle physics. However, this previous result was based on an incoherent spectroscopy technique in which the quantum transitions were disturbed by magnetic field fluctuations and measurement interference. In a substantial upgrade of the experiment, these decoherence mechanisms were suppressed and eliminated, culminating in the first coherent spectroscopy of an antiproton spin. The BASE team has now accomplished this for a period – called spin coherence time – of 50 seconds.  “This represents the first antimatter qubit and opens up the prospect of applying the entire set of coherent spectroscopy methods to single matter and antimatter systems in precision experiments,” explains BASE spokesperson Stefan Ulmer. “Most importantly, it will help BASE to perform antiproton moment measurements in future experiments with 10- to 100-fold improved precision.” While qubits are the basic building blocks of quantum computers, where they allow information to be stored not just in one of two states but via a potentially limitless superposition of those states, the antimatter qubit demonstrated by BASE is unlikely to have immediate applications outside fundamental physics. An even bigger leap in the precision of antiproton measurements is expected using BASE-STEP, which was designed to allow trapped antiparticles to be transported by road to magnetic environments that are “calmer” than the antimatter factory. “Once it is fully operational, our new offline precision Penning trap system, which will be supplied with antiprotons transported by BASE-STEP, could allow us to achieve spin coherence times maybe even ten times longer than in current experiments, which will be a game-changer for baryonic antimatter research,” says lead author of the paper Barbara Latacz. Image: Physicist Barbara Latacz working in the BASE experiment – credit: CERN