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The top quark, the heaviest and most short-lived elementary particle known, has long been thought to decay too quickly to form bound states. However, a new result from the CMS Collaboration, presented this week at the Rencontres de Moriond conference, strengthens last year's observation that top quarks may, in fact, briefly pair up with their antimatter counterparts. This fleeting bound state – known as toponium – would be the most massive composite particle ever observed, completing the family of quark–antiquark states bound by the strong nuclear force.
Most matter around us is made of atoms, in which electrons cling to protons through the electromagnetic force. But protons themselves are not elementary. They belong to a broad family of composite particles called hadrons, in which quarks are held together by the strong nuclear force. Among them, the simplest are pairings of a quark with its own antiquark, which provide an especially clean window on the workings of the strong force. For decades, such states have been known for every type of quark but the most elusive: the top.
First discovered more than 30 years ago at the Tevatron accelerator near Chicago, the top quark has been extensively studied ever since, with experiments at the LHC going so far as to measure quantum entanglement between top quarks and antiquarks. Even when produced alongside its antiquark, the top typically decays before any bound state can form. Yet the hundreds of millions of top quark–antiquark pairs produced at the LHC, effectively making it a top-quark factory, provide such an enormous dataset that the rarest phenomena can leave a detectable trace.
The first hints of toponium appeared in searches for heavy Higgs-boson-like particles that could decay into a top quark–antiquark pair. An unexpected excess of collision events was observed at a mass close to twice the mass of the top quark, which is more characteristic of a bound state rather than a new fundamental particle. Detailed studies by the CMS and ATLAS experiments confirmed this excess using events in which both top quarks decay into leptons (electrons or muons).
The new CMS study approaches the problem from a different angle, examining events in which one top quark decays into a bottom quark, a charged lepton and a neutrino while the other decays into quarks that produce sprays, or “jets”, of particles. “Isolating the signal in this decay channel was challenging,” says Otto Hindrichs, a researcher at the University of Rochester who developed a new AI-assisted technique to reconstruct these collision events.
“Instead of reconstructing the mass of the top quark–antiquark pair directly, we focused on the relative velocity of the top quark and antiquark,” explains Yu-Heng Yu, a graduate student involved in the analysis. “If they form a bound state, their relative velocity should be much smaller than when they are produced independently,”
These new techniques proved highly effective. They resulted in the observation of an excess with a statistical significance of more than five standard deviations – the gold standard for a discovery in high-energy physics. The result provides a new, statistically independent confirmation of toponium production.
“Toponium is heavier than the heaviest known atomic nucleus, oganesson, making it the most massive bound state ever observed,” says Regina Demina, leader of the CMS group at the University of Rochester. “Its discovery deepens our understanding of the strong nuclear force and its ability to bind the fundamental constituents of matter.”
Find out more on the CMS website.
roryalex Tue, 03/24/2026 - 11:35 Byline CMS collaboration Publication Date Wed, 03/25/2026 - 11:31According to the theory of supersymmetry, there is a mirror world of hypothetical particles that could help resolve several physics puzzles, such as the surprisingly small mass of the Higgs boson and the nature of dark matter. The ATLAS Collaboration at the Large Hadron Collider (LHC) has conducted new searches for these so-called supersymmetric (SUSY) particles using machine-learning techniques. The results of these searches, presented this week at the Moriond conference, have placed some of the strongest bounds yet on the properties of SUSY particles.
Supersymmetry proposes that each particle in the Standard Model has a “superpartner”. The higgsino is the SUSY counterpart of the Higgs boson and is the subject of many SUSY searches. But detecting the higgsino, if it exists, is far from simple. The higgsino would not appear on its own but as a mixture of other SUSY particles, creating states known as neutralinos and charginos. Theorists predict that the lightest neutralino could be stable and, therefore, a strong candidate for dark matter. The other, heavier neutralinos and charginos would decay into this stable SUSY particle. However, these decays are expected to produce very little energy and the resulting low-energy particles would be extremely difficult to detect.
By deploying machine-learning techniques, the ATLAS Collaboration has been able to significantly improve the experiment’s sensitivity to low-energy particles. ATLAS now reports the results of two new searches for signs of SUSY particles in analyses of data from the LHC’s second run, which was collected between 2015 and 2018.
One of these searches involved hunting for signs of a disappearing track left by a chargino decaying into a stable neutralino, which is invisible to the detectors, and a low-energy pion. The pion follows a highly curved trajectory that is extremely difficult to identify in a busy proton–proton collision, causing the chargino’s track to “disappear”. The ATLAS Collaboration additionally searched for signs of heavier neutralinos decaying into the lightest and only stable neutralino and two low-momentum leptons, such as electrons. The researchers deployed neural networks to search deep into the low-momentum region of pions and leptons to find signs of them being produced through the decay of SUSY particles.
No signs of these SUSY particles were observed in either of these searches. However, these results have now set some of the most stringent limits yet on the masses and lifetimes of charginos and neutralinos, superseding the longstanding limits set by the Large Electron–Positron Collider, the LHC’s predecessor.
These limits help guide future searches for SUSY particles at the LHC and the High-Luminosity LHC. The search continues for the mirror world of SUSY.
roryalex Thu, 03/19/2026 - 09:25 Byline Rory Harris Publication Date Thu, 03/19/2026 - 11:23The LHCb experiment at CERN’s Large Hadron Collider (LHC) has discovered a new particle consisting of two charm quarks and one down quark, a similar structure to the familiar proton, but with two heavy charm quarks replacing the two up quarks of the proton, thus quadrupling its mass. The discovery, presented at the ongoing Moriond conference, will help physicists better understand how the strong force binds protons, neutrons and other composite particles together.
Quarks are fundamental building blocks of matter and come in six flavours: up, down, charm, strange, top and bottom. They usually combine in groups of twos and threes to form mesons and baryons, respectively. Unlike the stable proton, however, most of these mesons and baryons, which are collectively known as hadrons, are unstable and short-lived, making them a challenge to observe. Producing them requires smashing together high-energy particles in a machine such as the Large Hadron Collider (LHC). These unstable hadrons will quickly decay, but the more stable particles that are produced as a result of this decay can be detected and the properties of the original particle can therefore be deduced.
Researchers have used this approach many times to find new hadrons, and the new particle just announced by the LHCb Collaboration brings the total number of hadrons discovered by LHC experiments up to 80.
“This is the first new particle identified after the upgrades to the LHCb detector that were completed in 2023, and only the second time a baryon with two heavy quarks has been observed, the first having being observed by LHCb almost 10 years ago,” says LHCb Spokesperson Vincenzo Vagnoni. “The result will help theorists test models of quantum chromodynamics, the theory of the strong force that binds quarks into not only conventional baryons and mesons but also more exotic hadrons such as tetraquarks and pentaquarks.”
In 2017, LHCb reported the discovery of a very similar particle, which consists of two charm quarks and one up quark. This up quark is the only difference between this particle and the new one, which has a down quark in its place. Despite the similarity, the new particle has a predicted lifetime that is up to six times shorter than its counterpart, due to complex quantum effects. This makes it even more challenging to observe.
By analysing data from proton–proton collisions recorded by the LHCb detector during the third run of the LHC, the LHCb Collaboration observed the new baryon with a statistical significance of 7 sigma, well above the threshold of 5 sigma required to claim a discovery.
“This major result is a fantastic example of how LHCb’s unique capabilities play a vital role in the success of the LHC,” says Mark Thomson, CERN Director-General. “It highlights how experimental upgrades at CERN directly lead to new discoveries, setting the stage for the transformative science we expect from the High-Luminosity LHC. These achievements are only possible thanks to the exceptional performance of CERN’s accelerator complex and the teams who make it all work and to the commitment of the scientists on the LHCb experiment.”
Further information:
LHCb presentation at Moriond is available here.
LHCb news article.
“If you place a large rock in a flowing stream, you can shelter objects located just downstream. It’s much the same with crystals and a beam of particles,” explains Francesco Velotti, applied physicist in the Accelerator Systems (SY) Department. This “crystal shadowing” technique has been successfully used in the Super Proton Synchrotron (SPS) since 2021 and is now entering a new phase, with the recent installation of a refined system made of three crystals ready for testing in the SPS.
As the last injector for the Large Hadron Collider (LHC), the SPS also supplies proton beams for the North Area fixed-target experiments. Proton beams are extracted from the SPS using a process known as slow extraction. As its name suggests, slow extraction delivers the beam over long time intervals, producing extended particle pulses. This allows the beam to be spread out in space and time, a key requirement for fixed-target experiments that rely on stable and uniform particle fluxes.
But slow extraction comes with a significant challenge. Compared with fast extraction, it leads to higher beam losses, which in turn result in increased damage to accelerator components. One of the most exposed elements is the electrostatic septum, a critical device that shaves off the circulating beam from the extracted beam. Beam losses in this region are particularly problematic, as they limit accessibility for maintenance and place constraints on long-term operation.
To address this issue, a team of experts from the SY Department (SY-ABT, SY-BI and SY-STI), with contributions from the Beams (BE) Department (BE-CEM), developed and installed a crystal-based system to avoid beam losses. When inserted into the beam, the bent silicon crystals act as a protective shield for the septum through a so-called shadowing effect. The position of the crystals can be remotely adjusted according to beam conditions. This development was carried out in the framework of the DECRYCE project (DEvelopment of CRYstals for Collimation and beam Extraction), a project created in 2022 to address the full research and development cycle for crystal systems at CERN, from design and engineering of crystal benders to silicon strips, assembly of crystal systems and experimental validation.
“The principle of crystal shadowing is rooted in the precise alignment of a thin, bent crystal so that a portion of the halo particles is deflected away from sensitive components,” explains Luigi Esposito, applied physicist in the SY Department. “Detailed beam dynamics simulations have been used to design and optimise these crystal systems, and they are carefully compared with real beam measurements to validate performance and assess potential operational gains.”
“We installed the first prototype – a system made of a single silicon crystal – in the SPS in 2021. It showed a 50% beam loss reduction, both in dedicated measurement campaigns and in operational conditions, where an AI-based control system was key to ensuring reliable performance, confirming the simulations,” adds Velotti.
The full system, consisting of several aligned bent silicon crystals, was installed in the SPS in January and is now entering its operational validation phase, as the SPS just finished its beam commissioning phase.
Reducing beam losses is a critical enabler for the next generation of fixed-target experiments. With the planned increase in proton intensity required for SHiP and the High-Intensity ECN3 (HI-ECN3) project, protecting components – and thus ensuring safe, reliable long-term operation of the SPS infrastructure – will be essential.
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To learn more, read the scientific article: Demonstration of non-local crystal shadowing at the CERN SPS.
anschaef Wed, 03/11/2026 - 13:23 Byline Anaïs Schaeffer Publication Date Thu, 03/12/2026 - 08:21In CERN’s academic environment – a place where academia runs industrial installations, where there must be the academic freedom necessary for the advancement of research and freedom of thought, and where there is a permanent come and go of our colleagues and with them their thousands of personal “bring-your-own” devices – cutting-edge research relies on an open yet to-be-protected digital ecosystem. CERN’s Computer Security Office, mandated to protect the operations and reputation of the Organization against any kind of cyberthreat, is well aware of its challenge to find the best balance between academic freedom, personal devices and the defence of our global scientific infrastructure. The right balance means protecting CERN’s operations and reputation while guaranteeing the privacy of our staff and users in their workplace. And this requires constant choices, as computer security is, by nature, intrusive.
To protect an account, a device, a system or even an organisation, deep insight is needed into their internal functioning in order to distinguish the good from the bad, the malicious from the benign, the targeted attack from unconscious errors, the (weird) use cases from deep abuse. Indeed, this is how network-based or host-based intrusion protection systems, spam filtering and antivirus and antimalware software work. And this obviously and directly collides with the wish for privacy, for non-intrusiveness, to be left alone. While at home it is entirely up to you how much privacy you want, in an organisation like CERN, the stakes are different and the Organization has an obligation to protect itself. It must therefore always be the goal of any computer security team, at CERN or anywhere else, to find the appropriate balance between the privacy of our individuals and the security of us all.
Therefore, since “privacy” rightly holds a firm place at CERN(1), the Computer Security Office runs its prevention, protection and monitoring tools in alignment with best industrial security standards but also with a deep-rooted consideration for “data protection” and your “privacy”. CERN’s Computing Rules (i.e. Operational Circular No. 5 and its Subsidiary Rules), which govern the work of the Office, provide the corresponding guardrails in how far “security” impacts “privacy”. Actually, while security can exist without privacy, privacy cannot exist without security, which does not imply that security is always paramount. By way of example, “privacy” is the key reason why the Computer Security Office promotes the use of encrypted communication channels while accepting that this inhibits any deep-packet inspection of the network traffic at CERN’s outer perimeter firewall. “Privacy” trumps “security”.
In other cases, however, the balance is more delicate. Take the CERN-provided antimalware protection as an example. The CERN IT department provides sophisticated software with remote forensics capabilities for a subset of centrally managed Windows computers (the so-called “hardened” PCs), but deploys a lighter version to all other Windows and MacOS devices owned by CERN (i.e. purchased on a CERN budget code)(2). For the latter, the antimalware software just reports virus findings to the central Windows team for follow-up, virus analysis and incident response, but does not grant the team (or the Computer Security Office) any remote investigation possibilities. Personal devices, furthermore, can get the CERN antimalware software for free without any strings attached. CERN “security” balanced with “privacy”.
Like the antimalware, CERN’s automatic network inspection of unencrypted traffic at the firewall level, the automatic analysis and filtering of any malicious domain resolution (at the DNS level), the automatic spam and malware filtering linked to the CERN email system, and the automatic collection and analysis of all user interactions with CERN computing services like LXPLUS, all touch upon sensitive if not personal data − including of a purely private nature(3). And due to this, but also due to the sheer size of CERN’s digital infrastructure, all such data is fully automatically processed with as little expert intervention as possible. Expert intervention always implies a professional need for incident triage and incident response, as is well documented in the Computer Security Office’s Privacy Notice (aka “RoPO”), Privacy Statement and the RoPOs of the individual IT services. Admittedly, this still requires a certain level of trust in the IT Department’s service managers and the members of the Computer Security Office (and strict accountability!). All of them have a special clause in their MERIT form stating that their “functions, allowing access to personal data or other confidential and/or sensitive information, imply strict conformance to the rules laid down in OC11 and OC5, in particular those governing confidentiality”. Any abuse of their function is considered a severe violation of the CERN Computing Rules (OC5) and would subsequently be subject to liabilities and sanctions. There is a zero-tolerance policy. There is no yellow card for misconduct. One red card, and they’re out.
So, in the end, “privacy vs security” boils down to trust. The balance between privacy and security at CERN is built on transparent processes, automation wherever possible, strict oversight of necessary human involvement, and trust in the professionalism and respectfulness of CERN’s Computer Security Office, the members of the IT department and any other expert within the Organization handling personal data. At CERN, “privacy” and “data protection” play a big role, but outside CERN...? How much more or less do we trust our colleagues compared to those folks running ChatGPT, Gmail, Instagram or TikTok cloud services? Or those providing external software suites or even the whole operating system to us? Isn’t it there that we pay for their “free” service with our data?
(1) It is important to recall that “privacy” and “data protection” are not identical concepts: privacy relates to an individual’s expectation of being left alone, while data protection governs how personal data is collected, used, accessed and safeguarded under defined rules such as the European General Data Protection Regulation (GDPR) and the CERN equivalent: OC11.
(2) CERN-managed and CERN-owned devices are also initially configured with local disk encryption and remote wiping capabilities as laptops tend to get stolen or lost. Without disk encryption, locally stored data can be accessed despite any password protection as the disk/memory itself is unprotected. For the same reason, remote wiping (like Apple’s “Find My”) prevents a thief from abusing the device in any way. In both cases, CERN IT provides such a functionality in a privacy-preserving manner.
(3) CERN’s OC5 tolerates the use of CERN’s computing facilities for personal use (see its annex) as long as this use is in compliance with the Computing Rules.
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Do you want to learn more about computer security incidents and issues at CERN? Follow our Monthly Report. For further information, questions or help, check our website or contact us at Computer.Security@cern.ch.
anschaef Wed, 03/11/2026 - 12:53 Byline Computer Security Office Publication Date Wed, 03/11/2026 - 12:49CERN Science Gateway has reached another milestone: the delivery of its 1000th science show!
Since opening its doors in October 2023, Science Gateway has welcomed nearly 900 000 visitors of all ages to explore the fundamental questions of the Universe. Among its most popular activities are the science shows – dynamic, interactive demonstrations led by CERN guides and tailored to a broad audience of different age levels, including school groups, families and the general public.
Designed to make complex scientific concepts accessible and entertaining, these live shows combine spectacular experiments, multimedia elements and audience participation. From the physics of particle collisions to the properties of superconductivity, electromagnetism and cryogenics, the science shows translate the research carried out at CERN into engaging visual experiences. Visitors might see superconductors levitate, follow particles through different detector layers or discover the beauty in phase transitions. Each demonstration is carefully crafted to spark curiosity while maintaining scientific accuracy.
Members of the CERN community are of course warmly invited to visit CERN Science Gateway with their family or friends and attend one of the science shows.
To register, please visit this page, and don’t forget to check the programme for the coming days.
Become a CERN guide and run your own super-cool science show (and more)!
To become a CERN guide, you can join the introduction course held every 3–4 weeks, which will give you an overview of what being a CERN guide entails. From there, further courses are available depending on what type of guide you would like to be.
Because, of course, CERN guides are needed everywhere at CERN. If you imagine yourself as a more ‘traditional’ guide, you should know that there are currently more than ten exciting visit points in CERN’s visits portfolio, such as the Antimatter Factory, the ALICE experiment (surface), the Alpha Magnetic Spectrometer (AMS) control room, the ATLAS experiment (surface), the CERN Control Centre (CCC), the Data Centre, the LHCb experiment (surface), the Synchrocyclotron (SC), the SM18 test facility and the newly inaugurated Linac2 visit point.
Indeed, CERN’s Visits Service and Visual Impact and Exhibitions Section recently collaborated on redesigning the Linac2 visit tour, which has just reopened to the public after several months of renovation work. The new tour offers visitors and guides alike an enriched, more immersive experience, designed to highlight the history and scientific significance of this major facility.
New Linac2 visit point. More photos here. (Image. CERN)So, fancy becoming one of the insiders? Join the introduction course, check the guides website or contact guides.manager@cern.ch.
And remember, becoming a guide can benefit you, too.
anschaef Wed, 03/11/2026 - 12:33 Byline Anaïs Schaeffer Publication Date Wed, 03/11/2026 - 12:28
From physics analysis and detector operations to software development and upgrade work, ATLAS PhD students make critical contributions to the Collaboration’s scientific mission while completing their degrees. This year’s ATLAS Thesis Awards drew from more than 200 eligible theses, reflecting both the scale of the Collaboration and the breadth of student research. From this pool, the Thesis Awards Committee reviewed 36 formal applications before selecting eight winners.
This year’s recipients are: Takumi Aoki from the University of Tokyo (Japan), Kartik Deepak Bhide from Albert-Ludwigs-Universität Freiburg (Germany), Antonio Jesús Gómez Delegido from Universitat de València (Spain), Simon Florian Koch from the University of Oxford (UK), Elena Mazzeo from Università degli studi di Milano (Italy), Ryan Roberts from the University of California, Berkeley and Lawrence Berkeley National Laboratory (USA), Stephen Nicholas Swatman from the University of Amsterdam (Netherlands) and Elliot Watton from the University of Glasgow and Rutherford Appleton Laboratory (UK).
“Students are the ‘soul’ of the ATLAS Collaboration,” said Jean‑François Arguin, ATLAS Thesis Awards Committee Chair. “They make up a third of ATLAS scientific authors and carry out much of the essential work that keeps ATLAS at the frontiers of scientific research. The quality and breadth of this year’s nominations made the Committee’s decision especially challenging, and we congratulate all nominees for their outstanding work.”
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Read more on the ATLAS website.
anschaef Wed, 03/11/2026 - 12:19 Byline ATLAS collaboration Publication Date Wed, 03/11/2026 - 12:17
During the recommissioning phase, the operations teams, together with equipment and machine-protection experts, worked around the clock to bring the Large Hadron Collider (LHC) back into operation. Finally, on the afternoon of Saturday, 7 March, stable beams for physics data taking were declared for the first time in 2026. This milestone marks the beginning of the final LHC data-taking run before the High-Luminosity LHC (HiLumi LHC) upgrade.
With Long Shutdown 3 (LS3) scheduled to begin at the start of July in the case of the LHC, the 2026 run will be short but densely packed. Every day counts, and the operations teams have mapped out a precise sequence of running phases to maximise the physics output during the machine’s final months.
The LHC restarted with just four bunches circulating per beam. Over the coming weeks, this number will gradually increase to more than 2400 bunches per beam. This intensity ramp-up is not simply a matter of injecting additional bunches: at each new intensity step, beam stability, beam losses and beam-induced effects – such as electron cloud and equipment heat-up – must be carefully assessed before proceeding further.
Once nominal intensity is reached, the LHC proton physics programme will begin, with around three weeks of low pile-up data taking in the ATLAS and CMS experiments. These lower collision rates provide fewer but cleaner events, which is ideal for precision measurements such as determining the mass of the W boson.
This will be followed by a high pile-up phase, pushing up luminosity to extend the integrated dataset beyond the already achieved Run 3 target and increasing the statistical reach for rare processes.
Later in the run, proton collisions will give way to around three weeks of lead-ion collisions, recreating the extreme conditions of the early Universe and producing the quark–gluon plasma that is studied by the LHC experiments, primarily ALICE.
The run will conclude with a two-week high-intensity test, in which bunches containing significantly more protons than in standard operation will circulate in the machine. These tests will probe the LHC’s behaviour under conditions closer to those expected at the HiLumi LHC and will help to identify both known and unexpected limitations that will have to be addressed during the upcoming four-year upgrade.
At the end of June, the LHC will fall silent. When it returns in 2030 as the HiLumi LHC, it will operate with a substantially higher collision rate, opening the door to deeper studies of known phenomena and increasing the chances of observing extremely rare processes.
These final months of running are therefore not just an ending, but an essential prelude to the LHC’s next chapter.
The Antimatter Factory roars back to life
CERN’s Antimatter Factory has also restarted its physics programme. After an unusually short year-end technical stop (YETS), the facility officially began its final six months of physics before LS3 at 17:30 on 27 February.
In just two intense weeks of recommissioning, the accelerator teams restored the full chain – from the first beam delivered by the Proton Synchrotron (PS) to the antiproton production target, through the Antiproton Decelerator (AD) and the ELENA (Extra Low ENergy Antiproton) ring – until antiprotons were once again reaching the experiments.
The experiments arrived at the starting line ready. Nearly all the collaborations were prepared to begin data-taking immediately, and two experiments – BASE-STEP and PAX – even managed to receive a few shots of beam during the decelerator set-up phase.
Together with the other experiments – ALPHA, ASACUSA, AEgIS, GBAR, PUMA and BASE – the programme continues the search for clues to one of the Universe’s deepest mysteries: why matter dominates over antimatter. By studying the properties of antimatter with ever-greater precision, these experiments aim to test fundamental symmetries of nature and explore questions such as how antimatter behaves in a gravitational field.
anschaef Wed, 03/11/2026 - 12:10 Byline Bettina Mikulec, Leader of the Operations Group (BE-OP) Publication Date Thu, 03/12/2026 - 12:05
IdeaSquare, the innovation space at CERN, has created a new workshop for the CERN community and visiting students. Named ‘The Forge’, the workshop is designed to support rapid prototyping from idea to iteration, and opened for bookings at the start of this year.
Constructed with assistance from the Site and Civil Engineering (SCE) Department, the new workshop brings the former 3D Printer Studio and two containers together to create one collaborative space. Featuring a large central worktable for ambitious builds and a modular peg wall for flexible set-ups, it offers the space and tools needed for experimental and inventive work. With easily accessible 3D printers and interactive smartboards, users can quickly build and experiment with prototypes.
“We started the process about a year ago when I was a visiting student here at IdeaSquare,” said Nick Lindsay, designer of the workshop. “It was missing a larger area to work together, which was limiting for visiting student groups.”
Most of these groups are made up of master’s students from a variety of different disciplines participating in the IdeaSquare Planet programme. This programme asks them to imagine what problems a new society started from scratch on an exoplanet would encounter, before applying their solutions to real-world scenarios.
“IdeaSquare’s educational programmes offer students a unique opportunity to work alongside CERN scientists and engineers, an experience ‘The Forge’ is designed to better facilitate,” explained Dina Zimmerman, Prototyping Facilitator at IdeaSquare.
The new workshop will also better serve the CERN community, who have benefitted from the free prototyping spaces provided by IdeaSquare since 2014. Over 200 CERN personnel from across the Organization use its spaces every year to learn about design-driven methodologies, take part in prototyping workshops and create or test prototypes for their experiments. Examples of prototypes designed there include elements for a Barrel Timing Layer for the High-Luminosity upgrade of the LHC, a Stirling cryo-cooler and a 3D-printed polystyrene-based plastic scintillator for the FASER experiment. Members of the CERN community can sign up for training on the use of the prototyping facilities or machines before booking a slot in the prototyping calendar.
To discover more projects and prototypes developed by members of the CERN community at IdeaSquare, come along to the “Prototyping at CERN” event on 15 April.
Lead designer of ‘The Forge’ Nick Lindsay and Prototyping Facilitator Dina Zimmermann have worked together to create the new space. (Video: CERN) ehatters Wed, 03/11/2026 - 10:42 Byline Jimmy Poulaillon Publication Date Thu, 03/12/2026 - 10:25The final laps before the major overhaul: CERN’s accelerator operators have just fired the starting pistol for the last run of the Large Hadron Collider (LHC). At the end of June, four years of work will begin to transform the LHC into a high-luminosity accelerator (the HiLumi LHC).
For now, let’s turn our attention to the first proton collisions of the year, which were recorded by the LHC experiments on Saturday, 7 March at 15h58.
After 11 years of high-energy operation, the LHC teams have acquired such expertise that it is easy to forget the complexity of this 27-kilometre-circumference machine located 100 metres underground, equipped with more than 9000 superconducting magnets, thousands of electrical circuits and hundreds of thousands of pieces of equipment, and operating at ‑271 °C thanks to the world’s largest cryogenic system.
“The restart of the CERN accelerator complex after the traditional winter shutdown was completed in record time,” says Matteo Solfaroli Camillocci, Head of LHC Operations. “The teams have a deep understanding of the machine and are demonstrating impressive finesse in their work. It’s a real team effort, and we are all looking forward to the last few months of operation.”
Several types of collisions are on the menu for these four months of operation, which are starting with nine weeks of proton collisions and will be followed by three weeks of operation with lead ions. The 2026 run will end with two weeks of tests with high-intensity proton beams: bunches containing 40% more protons than the standard LHC bunches will be circulated to test the impact on the equipment. Following on from the tests carried out last autumn, the aim is to study the behaviour of high-intensity beams, which will be part of everyday operation at the HiLumi LHC, and to identify any unforeseen limitations before the shutdown begins. However, at such high intensities, the beams will contain a limited number of bunches, as the current accelerator and experiments cannot handle a higher load.
29 June will mark the start of four years of major work, during which part of the LHC will be dismantled and replaced with innovative equipment that is currently in production. The HiLumi LHC, which will start operating in 2030, will generate a significantly higher number of collisions than the current LHC, allowing physicists to study known mechanisms, such as the Higgs boson, in greater detail and to observe possible new, very rare phenomena.
cmenard Fri, 03/06/2026 - 16:28 Byline Corinne Pralavorio Publication Date Sat, 03/07/2026 - 16:00The NA62 Collaboration has dramatically reduced the uncertainty in its measurement of an extremely rare particle decay, in results just presented at the 2026 La Thuile conference.
The study of rare decays gives physicists the chance to probe the Standard Model of particle physics. Researchers can determine what is known as the branching ratio of a decay, which describes how many particles decay through a particular process as a fraction of the total number of decays that occur. The branching ratio of the decay that the NA62 Collaboration has studied – the decay of a positively charged kaon into a positively charged pion and neutrino–antineutrino pair (written K+→π+νν) – can be predicted theoretically with a very high degree of precision. Thanks to this ‘theoretical cleanliness’, this particular kaon decay is extremely sensitive to new physics beyond the Standard Model but, with a predicted branching ratio of less than one in 10 billion, it is extremely rare and very challenging to observe.
The NA62 experiment was designed to study the K+→π+νν process in depth and therefore produces a lot of kaons, which is why it is also known as the “kaon factory”. The kaons are created by firing a high-intensity beam of protons from the Super Proton Synchrotron at a beryllium target. This produces nearly a billion particles every second, of which around 6% are kaons whose decay products can be studied in great detail using the NA62 detectors.
In 2024, the NA62 Collaboration reported having observed this process with a statistical significance of five standard deviations, the gold standard in particle physics for claiming a discovery. Now, the researchers have included the data recorded in 2023–2024 in their analyses and used improved data analysis techniques based on cutting-edge machine learning algorithms. The results, combined with the previous data taken since the experiment began, have significantly refined their understanding of the ultra-rare kaon decay.
With the full dataset, the NA62 Collaboration obtained an updated value of the K+→π+νν branching ratio of 9.6 +1.9 −1.8 × 10−11 , with an uncertainty 40% smaller than before.
“This is the most sensitive dataset we have analysed yet,” said lead data analyst Joel Swallow. “The fact that we can see clearly and measure with precision something so rare and elusive is a great success from a technological point of view.”
With the precision of the current result, the kaon decay appears to occur as predicted by theory and sets powerful constraints on new physics beyond the Standard Model.
“This stress test of the Standard Model is remarkable given the extreme rareness and theoretical cleanliness of the process that we investigated,” said NA62 spokesperson Giuseppe Ruggiero. “We have demonstrated once again that our current leading theory of nature has incredible predictive power.”
roryalex Wed, 03/04/2026 - 11:59 Byline Rory Harris Publication Date Wed, 03/04/2026 - 11:58British experimental particle physicist Mark Thomson is CERN’s Director-General from 2026 to 2030. In the video interview below, he answers questions about where particle physics stands today, his priorities for the next five years, the main challenges he foresees, his management style and how he spends his downtime.
Find out more about Mark Thomson.
German accelerator physicist and former leader of the High-Luminosity LHC project Oliver Brüning has taken the helm of the Accelerators and Technology (ATS) Sector as CERN prepares to enter the upcoming long shutdown (LS3). The ATS Sector includes four departments: Beams (BE), Engineering (EN), Accelerator Systems (SY) and Technology (TE).
Find out more about Oliver Brüning.
Gautier Hamel de Monchenault, Director for Research and Computing:
French particle physicist and former spokesperson of the CMS experiment Gautier Hamel de Monchenault now leads the Research and Computing (RCS) Sector, which consists of three departments: Experimental Physics (EP), Information Technology (IT) and Theoretical Physics (TH).
Find out more about Gautier Hamel de Monchenault.
Ursula Bassler, Director for Stakeholder Relations
German and French particle physicist and former President of the CERN Council Ursula Bassler joins CERN to lead the Stakeholder Relations (SR) Sector, which comprises the Stakeholder Engagement (SR-SE) and Education, Communications and Outreach (SR-ECO) Groups.
Find out more about Ursula Bassler.
Jan-Paul Brouwer, Director for Finance and Human Resources
Originating from the Netherlands and bringing with him a wealth of experience in HR and finance at various international and academic organisations, including the European Commission and the European Parliament, Jan-Paul Brouwer joins CERN to lead the Finance and Human Resources (FHR) Sector, which comprises three departments: Finance and Administrative Processes (FAP), Human Resources (HR) and Industry, Procurement and Knowledge Transfer (IPT).
Find out more about Jan-Paul Brouwer.
Spanish particle physicist and former Site and Civil Engineering Department Head Mar Capeáns nowtransitions to leading the new Site Operations (SO) Sector, in a role similar to that of a traditional Chief Operating Officer (COO). The sector includes three departments: Health, Safety and Environmental Protection (HSE) (whose Department Head reports directly to the Director-General), the new Organisational Support and Improvement (OSI) Department and Site and Civil Engineering (SCE).
Find out more about Mar Capeáns.
Originally from Italy, Enrica Porcari was previously Head of the Information Technology Department and now takes up the new role of Chief Information Officer (CIO), responsible for steering the Organization’s information technology strategy, governance and policy. This encompasses areas such as cybersecurity, data privacy and cross-organisational initiatives such as artificial intelligence (AI) and relevant external partnerships.
Find out more about Enrica Porcari.
Video interview with CERN’s Director-General, Mark Thomson, in February 2026. (Video: CERN)
ehatters Wed, 02/25/2026 - 17:02 Publication Date Thu, 02/26/2026 - 14:30
The vertiginous descent of equipment into the depths of the accelerator tunnels is always a captivating event. The stars of the show over the last few weeks have been the two gleaming cold boxes that have arrived in the new service tunnels of the High-Luminosity LHC (HiLumi LHC), close to the ATLAS and CMS experiments. These two enormous pieces of equipment, manufactured in Germany by the company Linde, are a key component of the future accelerator’s two new refrigerators.
The two refrigerators, which will cool the new magnet systems installed on either side of the ATLAS and CMS experiments to -271.3 °C (1.9 kelvins), are complex systems made up of a number of impressive pieces of equipment. The compressors and cold boxes, which were installed on the surface last December, will pre-cool the helium to -268.6 °C (4.5 kelvins). The last few degrees needed to reach -271.3 °C, less than 2 degrees above absolute zero, will be gained by lowering the pressure of the helium circulating in the magnet cryostats and using four cold compressors connected in series and integrated into one of the cold boxes that have just been delivered.
In parallel, the cryogenic lines that will transport the helium are being installed underground. The teams have already completed the first phase of the installation work.
Two big cold boxes have been lowered in the new High-Luminosity LHC (HiLumi) underground galleries. They are part of the new refrigeration system for the major upgrade of the LHC. (Video: CERN)roryalex Wed, 02/25/2026 - 15:40 Byline Corinne Pralavorio Publication Date Fri, 02/27/2026 - 15:31
With more than 6000 scientists, engineers, technicians, administrators and students, CMS is one of the world’s largest scientific collaborations. From 1 January 2026 to 31 August 2028, Anadi Canepa has the important role of representing the Collaboration as its Spokesperson. Joining her as deputies are Hafeez Hoorani, who continues in his present role until 31 August 2026, and the newly appointed Florencia Canelli, who will remain in office until 31 August 2028.
Previous Spokesperson Gautier Hamel de Monchenault left the role early, at the end of 2025 instead of in August 2026, to become CERN’s Director for Research and Computing. The Collaboration thanks him for his work on its behalf and wishes him all the best going forward.
Anadi Canepa is a senior scientist at Fermi National Accelerator Laboratory (Fermilab). She began her research with the CDF experiment at the Tevatron, focusing on searches for new phenomena and the Higgs boson and contributing to upgrades of the silicon tracker and trigger system (PhD, Purdue University, 2006). In 2015, she became a scientist at Fermilab and joined the CMS Collaboration. She was appointed CMS Deputy Spokesperson during Gautier Hamel de Monchenault’s term of office (2024–2025).
Hafeez Hoorani received his PhD in Experimental High-Energy Physics from the DPNC, University of Geneva, in 1996. He was part of the L3 experiment at LEP, where he was responsible for the level 1 charge particle trigger. He joined CMS in 1995 and, since then, has contributed to its muon system in various capacities.
Florencia Canelli is Professor of Physics at the University of Zurich. She began her research at the D0 experiment at the Tevatron (PhD, University of Rochester, 2003), where she measured the properties of the top quark. Since joining the University of Zurich and CMS in 2012, she has held several leadership roles within the Collaboration.
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Read more on the CMS website.
anschaef Wed, 02/25/2026 - 11:43 Byline CMS collaboration Publication Date Wed, 02/25/2026 - 11:38Many activities are currently progressing across the accelerator chain as the complex moves steadily towards full operation. In the injectors, beam commissioning is advancing well, with the highlights being the start of the physics programme at ELENA on 20 February and the ongoing scrubbing run in the SPS.
The SPS has just completed its first week of beam commissioning. Physics delivery beams have been set up in the SPS ring and low-intensity beams have been prepared for both fast and slow extraction to serve the downstream machines and experimental facilities. The machine has now entered the intensity ramp-up phase during the so-called scrubbing run. This is a crucial commissioning step, required whenever the beam pipe has been opened to air for interventions or routine maintenance, during which surfaces inevitably become contaminated through atmospheric exposure. Although mitigation measures are implemented during these interventions, subsequent surface conditioning with beam is almost always necessary.
As beams circulate in the machine, they induce electromagnetic fields in the surrounding vacuum chambers and equipment. This can lead to local heating and outgassing. In addition, secondary electron emission from insufficiently conditioned surfaces may generate local concentrations of electrons. These electrons are accelerated by the passing beam and bounce off the chamber walls, releasing further electrons in a process known as multipacting. The resulting electron clouds can further degrade the vacuum. If the pressure rises excessively, sensitive equipment may be at risk. For this reason, the beam is injected and stored in a carefully controlled manner, ensuring that the vacuum remains at acceptable levels, below interlock thresholds, while efficiently conditioning the surfaces. Typically, about one week of scrubbing is required before the maximum beam intensities can be reached. For LHC Injectors Upgrade (LIU)-type beams, which will ultimately serve the High-Luminosity LHC (HL-LHC), this corresponds to 288 bunches at 2.3×10¹¹ protons per bunch.
Meanwhile, in the LHC, the final steps before beam injection are under way. First beam had initially been scheduled for 21 February. However, on 11 February a vacuum leak was detected on an edge-welded bellow of a tertiary collimator at Point 2. This type of vacuum bellow is known to represent a structural weak point under certain operating conditions and a dedicated task force was launched in 2025 to study mitigation strategies in view of HL-LHC operation. The leak could not be repaired in situ and the collimator had to be replaced.
The duration of such an intervention is largely dictated by the bake-out of the affected vacuum sector to restore ultra-high vacuum conditions. The vacuum sector concerned is one of the largest in the LHC, making the operation particularly delicate and time-consuming. Given that the intervention was unavoidable and that the second tertiary collimator in the same sector (one horizontal and one vertical) had accumulated a similar number of operational cycles – and therefore presented a comparable risk profile – it was decided to replace both units during the same stop.
A view of the two tertiary collimators being exchanged at Point 2. (Image: CERN)The intervention was carried out in a precise and efficient manner, with close coordination between the many groups involved, including vacuum, collimation, transport, beam instrumentation and cryogenics. The activities are expected to be completed on 26 February, after which the machine will be handed back for the final preparations. Hardware commissioning and machine checkout will be finalised in parallel. As a consequence, first beam injection into the LHC is now scheduled for 27 February, approximately six days later than originally planned.
Once beam is circulating, an intensive nine-day commissioning period will begin. During this phase, the accelerator will be progressively set up for physics operation. This includes orbit correction, optics measurements, collimator alignment, verification of machine protection systems and numerous other checks required to ensure safe and reliable operation at high energy. Only after this comprehensive commissioning phase will the LHC be ready to deliver stable beams for physics and the gradual intensity ramp-up begin.
With Run 3 entering its final stretch and Long Shutdown 3 (LS3) on the horizon, every commissioning step is both a preparation for the present and an investment in the future. The coming days will be decisive as beam returns to the LHC and commissioning moves into its most intense phase.
anschaef Wed, 02/25/2026 - 11:27 Byline Matteo Solfaroli, Deputy Leader of the Operations Group (BE-OP) Publication Date Wed, 02/25/2026 - 11:24Arts at CERN is delighted to announce that Geneva-based French-Congolese artist Monika Emmanuelle Kazi has been selected for the second edition of Resonance. This annual residency programme was launched in November 2024 by CERN, the Republic and Canton of Geneva and the City of Geneva, with the support of the CERN & Society Foundation. Designed for Geneva-based artists, Resonance offers a unique opportunity for artistic experimentation through close exchange with CERN’s scientific community and research environment.
Monika Emmanuelle Kazi holds a master’s degree in Visual Arts from HEAD – Genève. Her interdisciplinary practice engages with haptics and machine learning, resulting in organic installations that combine video, performance and writing. Drawing on objects, family archives and research materials, her installations form systems of visual and everyday references that she calls “iso-objects” – a term inspired by the International Organization for Standardization (ISO). Situated between documentary and fiction, Kazi’s work weaves personal memory into broader global narratives.
For the Resonance residency, Kazi will develop Crystalline Memories, a project exploring perceptions of the future through the lenses of futurology, prospective studies, divinatory practices, cosmogonies and cosmology. Her artwork will draw on research conducted at CERN, particularly the CLOUD and CAST experiments. Through immersion in CERN’s ecosystem, Kazi aims to connect scientific research with reflections on diasporic memory and its erosive forces. Inspired by archetypal myths and cosmogonies, Crystalline Memories will poetically examine the construction of knowledge, the imagination of the future and the fragile memories through which we attempt to navigate both.
“With over 83 applications received, spanning a wide variety of practices, Resonance is establishing itself as an attractive programme that fosters research and experimental practices while connecting the Republic and Canton of Geneva and the City of Geneva’s cultural scene with CERN’s vibrant scientific context and social fabric. Arts at CERN has been delighted by the growing interest in the programme and looks forward to welcoming Monika Emmanuelle Kazi for the second edition of Resonance,” says Giulia Bini, Head of Arts at CERN.
“The City of Geneva was delighted by the breadth and quality of the applications received for the second Resonance residency. The creativity and diversity of the projects are testament to the relevance of this programme, which offers artists a rare opportunity for in-depth dialogue with CERN’s scientific community and provides the members of the jury with a space for exciting discussions about distinctly exploratory projects. This fruitful encounter between artistic imagination and fundamental research affirms the richness of such a partnership, which helps to broaden the diversity of voices and perspectives within our cultural ecosystem,” explains Sophie Sallin, Cultural Advisor for the City of Geneva.
“The Canton of Geneva is committed to promoting a rich culture that is open to other fields of knowledge. We are delighted to be involved in the Resonance artistic residency programme, which builds bridges between artistic creation and scientific research. This initiative also underlines the commitment of a world-renowned scientific organisation to its host city and illustrates the special ties that unite Geneva and CERN through shared cultural enrichment,” says Thierry Apothéloz, President of the State Council of the Republic and Canton of Geneva.
The jury was composed of Giulia Bini, Curator and Head of Arts at CERN; Séverine Fromaigeat, Director of the Barbier-Mueller Museum; Chiara Mariotti, particle physicist at the CMS experiment at CERN; Sophie Sallin, Cultural Adviser for the City of Geneva; and Jérôme Soudan, Cultural Adviser for the Republic and Canton of Geneva.
Following its second edition, the Resonance residency programme will launch a new special edition for 2026.
rodrigug Mon, 02/23/2026 - 15:30 Publication Date Tue, 02/24/2026 - 15:30
In mid-November, CERN was subjected to another phishing attack that tried to lure people to open a malicious link and provide their CERN credentials on a fake CERN Single Sign-On page. While many of us detected and reported the scam, unfortunately up to 11.2% fell for the bait and potentially exposed their password. But, luckily for them, this was just an exercise…
So what did these phishing emails look like? Like any other “standard” package of spam and scam emails that the CERN mail filters block on a daily basis, they looked innocent enough. Simple. Maybe credible. Or not, as they could all also be recognised as dodgy, weird, suspicious or just not for us. They all came from a non-CERN domain, as can be seen in the “From” field of the email: “cofeesuppli3r.you”, “365mailserv.bk”, “kern.bz”, etc. Their message text resembled the “standard” spam. In fact, standard spam mails were used as inspiration for the exercise. And the embedded links did not actually point to the CERN SSO (“auth.cern.ch”) but to external URLs like www[.]hrsupportint[.]com or www[.]doctorican[.]de. Find below six screenshots of the “malicious” emails:
Would you have fallen for and clicked on any of them? Interestingly, of those who did, the “CERN password expires today” from “Pauline Cuvitrina” got the most clicks (50%), followed by the “important update on contracts” (31%) from the “Secretary service” and “DHL” (14%) from “Saniu Walliv”, while just a few people were convinced to have “earned a free coffee” or had an “MS365 Emails problem”(1). Below you can see the distribution per subject and the click rates per department.
The average click rate was about 6%, with variations up to 11.2%(2), but still all in the same ballpark given the statistical error. Actually, one can create any click rate as the rate depends largely on the sophistication of the message text: in another exercise, the CERN Computer Security Office succeeded in getting a click rate of more than 80% from about 120 IT specialists attending an IT conference who were invited by a fake email to “Download your voucher for a free beer in the hotel lobby here”.
While our spam filters and the recently concluded roll-out of two-factor authentication should already provide sufficient protection and usually detect and block such emails, defence-in-depth is better. “Security” is like Swiss Emmental cheese: you need several layers to cover all holes. Hence, next time, before you are tempted to click, please remember: STOP – THINK – DON’T CLICK when you see such an email (or, for that matter, an SMS, WhatsApp message, QR code or plain URL), in order to help protect the Organization. Thanks a lot!
(1) The EP Department with its many users was spared this time as rumours and warnings about the phishing campaign had already made the rounds via the usual communication channels and would have rendered the exercise less useful. (2) The “Dark Lord” email seemed too obvious and was not sent at all in the end. ________ Do you want to learn more about computer security incidents and issues at CERN? Follow our Monthly Report. For further information, questions or help, check our website or contact us at Computer.Security@cern.ch. anschaef Mon, 02/23/2026 - 14:04 Byline Computer Security Office Publication Date Wed, 02/25/2026 - 08:58
In the first few microseconds after the Big Bang, the Universe was in an extremely hot and dense state of matter known as quark–gluon plasma (QGP), which can be reproduced with high-energy collisions between heavy ions such as lead nuclei. In a paper published today in Nature Communications, the ALICE Collaboration reports observing a remarkable common pattern in proton–proton, proton–lead and lead–lead collisions at the Large Hadron Collider (LHC), shedding new light on possible QGP formation and evolution in small collision systems.
Physicists initially believed that colliding small systems, such as protons, could not generate the extreme temperatures and pressures needed to form QGP. But in recent years, signatures of QGP have been observed in proton–proton and proton–lead collisions at the LHC, indicating that the size of the collision system may not be a limiting factor in QGP creation.
A key signature of QGP formation is anisotropic flow, where the particles produced in a collision are not emitted evenly but in preferred directions. For particles moving at intermediate speeds (or momenta), this anisotropic flow depends on the number of quarks they contain: particles that are made up of three quarks (baryons) exhibit stronger flow than those that are composed of two quarks (mesons). The leading explanation for this difference is something called quark coalescence – the process through which the quarks in the QGP combine into larger particles. And as baryons contain one more quark than mesons, they inherit more flow.
In its new study, the ALICE Collaboration measured the anisotropic flow of multiple meson and baryon species produced in proton–proton and proton–lead collisions, by carefully isolating the particles that were genuinely flowing together. The analysis showed that, like in heavy-ion collisions, the anisotropic flow was much stronger for baryons than for mesons at intermediate momenta.
(Right) A proton–proton collision at the LHC in which many particles were created and tracked by the ALICE detector. (Left) Illustration of the anisotropic flow of mesons and baryons that ALICE has studied using data from such collisions, with the large arrows representing the preferred directions. (Image: ALICE/CERN)“This is the first time we have observed, for a large interval in momentum and for multiple species, this flow pattern in a subset of proton collisions in which an unusually large number of particles are produced,” says David Dobrigkeit Chinellato, Physics Coordinator of the ALICE experiment. “Our results support the hypothesis that an expanding system of quarks is present even when the size of the collision system is small.”
The ALICE researchers went on to compare the new flow measurements to predictions from simulations that assume QGP formation and its evolution. They found that models that incorporate the anisotropic flow of quarks and their subsequent coalescence into mesons and baryons successfully explain the observed flow pattern, whereas models that exclude either process fail to capture it. However, even the successful models are not exactly right. There are still discrepancies between the models and data that are largely linked to uncertainties in the modelling of the proton’s substructure and the initial geometry of the collisions.
“We expect that, with the oxygen collisions that were recorded in 2025, which bridge the gap between proton collisions and lead collisions, we will gain new insights into the nature and evolution of the QGP across different collision systems,” said Kai Schweda, ALICE Spokesperson.
roryalex Fri, 02/20/2026 - 16:43 Byline ALICE collaboration Publication Date Fri, 03/20/2026 - 11:40The CMS Collaboration has shown, for the first time, that machine learning can be used to fully reconstruct particle collisions at the LHC. This new approach can reconstruct collisions more quickly and precisely than traditional methods, helping physicists better understand LHC data.
Each proton–proton collision at the LHC sprays out a complex pattern of particles that must be carefully reconstructed to allow physicists to study what really happened. For more than a decade, CMS has used a particle-flow (PF) algorithm, which combines information from the experiment’s different detectors, to identify each particle produced in a collision. Although this method works remarkably well, it relies on a long chain of hand-crafted rules designed by physicists.
The new CMS machine-learning-based particle-flow (MLPF) algorithm approaches the task fundamentally differently, replacing much of the rigid hand-crafted logic with a single model trained directly on simulated collisions. Instead of being told how to reconstruct particles, the algorithm learns how particles look in the detectors, like how humans learn to recognise faces without memorising explicit rules.
When benchmarked using data mimicking that from the current LHC run, the performance of the new machine-learning algorithm matched that of the traditional algorithm and, in some cases, even exceeded it. For example, when tested on simulated events in which top quarks were created, the algorithm improved the precision with which sprays of particles – known as jets – were reconstructed by 10–20% in key particle momentum ranges.
The new algorithm also allows a collision to be fully reconstructed far more quickly than before, because it can run efficiently on modern electronic chips known as graphics processing units (GPUs). Traditional algorithms typically need to run on central processing units (CPUs), which are often slower than GPUs for such tasks.
“New uses of machine learning could make data reconstruction more accurate and directly benefit CMS measurements, from precision tests of the Standard Model to searches for new particles,” says Joosep Pata, lead developer of the new MLPF algorithm. “Ultimately, our goal is to get the most information out of the experimental data as efficiently as possible.”
While the new algorithm was tested under current LHC data conditions, it is predicted to be even more useful for data from the High-Luminosity LHC. Due to start running in 2030, the LHC upgrade will deliver approximately five times more particle collisions, posing a significant challenge to the LHC experiments. By teaching detectors to learn directly from data, physicists are not just improving performance, they are redefining what is possible in experimental particle physics.
Find out more about the algorithm on the CMS website and more about machine learning in particle physics through this CERN colloquium.
ehatters Thu, 02/12/2026 - 11:58 Byline CMS collaboration Publication Date Wed, 02/18/2026 - 12:35
This Valentine’s Day, CERN shines a light on its HEARTS testing facility, loved by those who recently tested their components for the harsh conditions of space.
Late last year, the Large Hadron Collider ended a record-breaking year by colliding lead ions. The HEARTS@CERN facility took advantage of this period to test radiation effects with lead ions. Over the course of two weeks in November and December 2025, 16 companies and research institutes spent more than 200 irradiation hours at CERN testing electronic components and devices for use in space and for high-energy physics applications.
The HEARTS (High-Energy Accelerators for Radiation Testing and Shielding) project, funded by the European Union, is establishing two new European radiation testing facilities for space applications, one at CERN and the other at the GSI Helmholtz Centre for Heavy Ion Research in Germany. Unique in Europe, these two facilities offer very-high-energy heavy-ion electronics testing, so that teams can see how their electronics hold up against particularly strong and penetrative radiation that they could be exposed to in space.
Among the components tested were solid-state drive (SSD) memory storage devices for a Belgian start-up focusing on computers for satellites, as well as printed circuit board (PCB) components for an Italian company building a satellite to investigate the Apophis asteroid during its close approach to Earth in 2029.
The recent tests were the second industrial user pilot campaign at CERN, following the 2024 run that welcomed ten companies and research institutes. Six of the sixteen users participating in the 2025 run paid for access, while the rest either received beamtime hours through their association with the project or applied through the RADNEXT project, which offers transnational access to radiation facilities in Europe.
The HEARTS@CERN facility will host another user run in the summer of 2026 before a short break in 2027 as CERN’s accelerator complex shuts down for maintenance. Calls for industry and scientific users for the 2026 campaign will be announced on the project website.
anschaef Wed, 02/11/2026 - 13:27 Byline Thomas Brent Kate Kahle Publication Date Thu, 02/12/2026 - 10:25
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