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Intuitive Software Suite Revolutionizes DNA Structure Generation and Analysis

3 June 2026 at 18:01

In a groundbreaking advancement for molecular biology and computational chemistry, researchers at the University of Amsterdam’s Van ’t Hoff Institute for Molecular Sciences have unveiled an innovative software suite designed to accurately model DNA structures within biomolecular assemblies. Dubbed MDNA, this state-of-the-art toolkit empowers scientists across multiple disciplines—including biochemistry, molecular biology, bioinformatics, and biophysics—to visualize, analyze, and simulate DNA with unprecedented atomic precision. This development promises to significantly deepen our understanding of DNA behavior in complex biological environments, advancing both fundamental research and applied sciences.

At the heart of MDNA’s innovation is its ability to generate three-dimensional atomic coordinates for double-stranded DNA molecules, regardless of their shape or complexity. Unlike traditional tools that might rely heavily on generalized models or limited structural libraries, MDNA adopts the rigid base formalism originally embodied in the Curves+ code, a well-regarded computational framework for nucleic acid conformation analysis. This approach treats each base pair within the DNA as an individual rigid unit, allowing for a finely tuned representation of the molecule’s structural intricacies.

What sets MDNA apart from many existing molecular modeling tools is its flexibility and adaptability. Users can effortlessly design DNA molecules following virtually any arbitrary spatial curve, making the creation of highly customized and intricate DNA architectures more accessible than ever before. Moreover, the software supports the modification and extension of pre-existing DNA structures, facilitating iterative design and refinement processes crucial for research that explores DNA-protein interactions and biomolecular mechanics.

The software’s user-friendly nature further democratizes molecular modeling. It has been extensively tested by students and researchers from diverse scientific backgrounds—many with minimal prior programming experience—and has proven accessible for both novices and experts. Accompanying the software are comprehensive tutorials and demonstrations, positioning MDNA as not only a research tool but also as an invaluable educational resource suitable for workshops and classroom environments.

A vital component of MDNA’s structural modeling capabilities comes from the collaborative implementation of an advanced energy function, developed in partnership with the group led by Helmut Schiessel at TU Dresden. This energy function facilitates rapid equilibration of DNA structures while accurately modeling essential physical properties such as stiffness, flexibility, and intrinsic mobility. By incorporating physical constraints, it enables the simulation of biologically relevant phenomena like DNA supercoiling without the computational overhead typically associated with all-atom simulations.

In addition to its robust structural generation features, MDNA excels as an analytical tool. It can process DNA configurations derived from molecular dynamics simulations, facilitating a seamless integration between modeling and analysis within a unified workflow. This integration is crucial for researchers investigating the dynamic nature of DNA and its interactions with proteins and other cellular components, as it reduces the barriers between data generation, exploration, and hypothesis testing.

The scope of MDNA extends beyond just double-stranded DNA; the software includes a growing library of sixteen nucleobase types with plans for future expansion, offering an expanding toolkit to model various DNA modifications and analogs. Such versatility is especially pertinent as synthetic biology and epigenetics increasingly demand precise modeling tools capable of representing non-canonical DNA structures and chemical modifications.

MDNA’s efficient computational framework leverages simplifications that avoid simulating every atom explicitly, allowing structures to reach equilibrium within seconds. This significant reduction in computational time without sacrificing accuracy presents substantial advantages for high-throughput DNA modeling tasks, enabling rapid prototyping of DNA-based nanodevices or exploring a vast landscape of theoretical DNA conformations.

The open-source nature of the MDNA suite invites broad usage and collaborative development within the scientific community. Available publicly via repositories like Figshare and Github, it encourages transparency, reproducibility, and community-driven enhancements. This openness not only fosters innovation but also helps establish MDNA as a standard platform for DNA modeling in both academic and industrial research contexts.

By bridging detailed atomic-level resolution with high computational efficiency and an intuitive interface, MDNA fills a critical gap in the current toolbox for molecular simulation. It offers molecular scientists an indispensable means to unravel DNA’s structural complexities, enhancing our grasp on biological mechanisms ranging from gene regulation to chromosome packaging.

As research increasingly focuses on the interplay between DNA and proteins within the crowded cellular environment, tools like MDNA pave the way for more accurate models that can directly inform experimental design and therapeutic development. These models may, in turn, accelerate progress in fields such as drug discovery, gene editing, and synthetic biology, where precise structural understanding is paramount.

The collaboration between experimental insight and computational ingenuity as demonstrated in MDNA exemplifies the future of molecular sciences—where software not only supports but actively shapes research frontiers. With the support of comprehensive documentation and educational outreach, MDNA is poised to become a cornerstone technology for any scientist captivated by the elegance and complexity of DNA.


Subject of Research: Molecular modeling and simulation of DNA in biomolecular assemblies

Article Title: MDNA: A comprehensive molecular modeling toolkit for DNA in biomolecular assemblies

Web References:
DOI link to the published paper

Image Credits: HIMS / University of Amsterdam

Keywords: Computational chemistry, Biochemistry, Molecular biology, Bioinformatics, Biophysics, DNA modeling, Molecular simulation, DNA-protein interactions, Molecular dynamics

How virtual power plants could provide energy for data centers

3 June 2026 at 17:51

Would you take a payment to ramp down your electricity use? Would it change anything if you were doing so to help power a local data center?

Google just signed a new deal to help pay for a virtual power plant (VPP) in the largest power grid in the US. The agreement is with Voltus, a leading VPP and distributed energy resources platform.

Voltus will set up the virtual power plant, grouping together devices like electric vehicles and smart thermostats. It’ll pay customers to participate, and the company will dial back power or use the stored energy during times when the grid is stressed. Google will foot the bill for setting it up, and the extra capacity generated by the project will help run its data centers in the region.

This is one of the most concrete examples so far of a tech giant using a VPP to help meet energy demand for data centers. But there are still some lingering questions about just how far this sort of program can go, and what the limits are.

Last year, it felt as if everyone was talking about data center flexibility. A high-profile study from Duke University found that if data centers agreed to decrease their energy demand for roughly 40 hours per year, a whole bunch of them (about 100 gigawatts’ worth) could come online without making new power plants or transmission equipment necessary.

The underlying reason is that our power grid is designed not for our average energy use, but for the absolute maximum: the brutally hot July evening when everyone is blasting their air conditioners, watching Love Island, and microwaving popcorn. If a data center is willing to refrain from pulling so much power during those high-stress times, the grid can happily support it the rest of the year.

One lingering question here is about incentives: How would you get data centers to agree to this? After all, they might not have a very flexible load, especially now that AI use is more widespread—training a model can easily be delayed or shifted, but customer demand is more immediate. Giving up computing capacity could mean losing revenue.

Regulation is one approach that could work here. One proposal in the US would allow new data centers to come online years sooner if they agree to lower demand when the grid is nearing its max.  And a new Texas law requires large users to switch to backup power or curtail their demand in emergency situations.

Another approach is for data center operators to pay for other people to be flexible.

Voltus announced a new program in September that allows data centers to finance flexibility on their local grid. The company calls it “Bring your own capacity.” Google is now the first named customer taking advantage of this program.

In the new agreement, Voltus will pay people who agree to participate in the virtual power plant. The plant will be part of PJM, the grid that covers much of the US East Coast. The company says it will be able to aggregate up to 100 megawatts of distributed energy resources each year. The plant should be operational in 2027, according to Voltus.

This isn’t Google’s first foray into flexibility; the company has agreements with utilities across the US to limit or shift its own energy demand, which can help free up grid capacity. As the company pointed out in a blog post earlier this year, though, there are limits on how flexible a data center can be, and not every facility will be able to ramp down its power demand.

“There is no one solution for expanding grid capacity and we’re continuing to explore all options, including the many avenues for load flexibility,” said Michael Terrell, Google’s global head of advanced energy, in an emailed statement in response to written questions.

Once again, I’m wondering about incentives here. These companies are asking homes and businesses to be flexible. Will they agree?

A recent study in California looked at local people’s willingness to participate in managed electric-vehicle charging. Essentially, the program pays people to give up control of when they charge their EVs. This is another way to help smooth out electricity demand and ease the burden on the grid.

The problem? Not many people signed up. With no economic incentive, only 1% of EV owners enrolled in managed charging. At $40 per month (about 15% of their power bill), only 4.6% did.

This is a different situation and a different region from the one in which Google is working with Voltus. (It’s worth noting that the companies aren’t sharing how much they plan to pay the participants, which will obviously be a big determinant in participation for this kind of project.) 

But this study shows that even with money on the table, people may not always jump at the chance to cede control of their electricity demand. And it certainly feels relevant that about 70% of Americans oppose AI data centers in their area, according to recent Gallup polling

Being flexible sounds like a great idea in theory, and these financed VPPs could provide an immediate route to meeting energy demand. But as we move from idea to implementation, it’ll be interesting to see whether trial runs work as intended.  

This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here

Scientists Identify Microbes Producing Climate-Regulating Gas in India’s Busiest Estuary for the First Time

3 June 2026 at 17:48

Scientists have made a remarkable breakthrough in understanding the microbial processes behind the production of a crucial climate-regulating gas in one of India’s busiest estuarine ecosystems. In a pioneering study led by researchers from the Department of Chemical Oceanography at the Cochin University of Science and Technology (CUSAT), Kochi, the intricate dynamics of dimethylsulfoniopropionate (DMSP) degradation in the Cochin Estuary have been mapped comprehensively for the first time. This estuary, renowned for its intense biological productivity and complex interactions influenced by monsoon-driven hydrodynamics, has long remained understudied in the context of sulfur biogeochemistry despite its global climatic importance.

DMSP, a sulfur-containing compound synthesized predominantly by marine phytoplankton and macroalgae, serves as a key precursor to dimethylsulfide (DMS). Once released by bacterial decomposition, DMS enters the atmosphere where it contributes to cloud formation by acting as nuclei for cloud condensation. This natural feedback mechanism plays a subtle yet profound role in the earth’s radiative balance and climate regulation. Although extensive research has been conducted in temperate and open ocean waters, tropical estuarine systems like the Cochin Estuary have been largely omitted from this global sulfur cycle narrative.

Between 2015 and 2018, the investigative team undertook extensive fieldwork along the length of the Cochin Estuary, strategically sampling fifteen stations spanning upper, middle, and lower reaches to capture spatial variability. These sites were visited through distinct seasonal phases — pre-monsoon, monsoon, and post-monsoon — providing temporal insights into how monsoonal shifts impact the biogeochemical regime. Analytical methods integrated gas chromatography to quantify DMSP and DMS concentrations systematically across water and sediment matrices, paired with cutting-edge 16S rRNA gene sequencing to characterize the resident bacterial communities responsible for DMSP metabolism.

A striking revelation from the study indicates that sediment environments are hotspots for both higher DMSP accumulation and bacterial abundance when compared to overlying water columns. Sediment DMSP levels and bacterial counts per gram generally exceeded those measured per millilitre in water, confirming sediments’ pivotal role as active sites for sulfur cycling processes. This spatial pattern highlights the often-overlooked benthic zone’s biochemical significance, especially in estuarine systems influenced by complex hydrodynamics and nutrient influxes.

Salinity and temperature fluctuations associated with monsoonal variability emerged as critical drivers shaping DMSP concentrations and microbial dynamics along the estuary. The research documented peak DMSP concentrations at a mid-estuary station during pre-monsoon conditions, coinciding with elevated salinity and temperature. These environmental parameters are well-known to influence phytoplankton productivity, underscoring a direct linkage between climatic seasonality and biogenic sulfur fluxes. The seasonal coupling of physical and biological factors reflects the sensitivity of DMSP-mediated pathways to broader climate oscillations.

The bacterial taxa isolated from sediment samples reveal a fascinating diversity of organisms capable of utilizing DMSP as their sole carbon source. Specifically, two γ-Proteobacteria species — Acinetobacter calcoaceticus and Acinetobacter beijerinckii — along with two Firmicutes representatives — Bacillus cereus and Lysinibacillus fusiformis — exhibited robust growth on DMSP substrates. The presence of these taxa highlights the complexity of microbial consortia involved in sulfur cycling and points to unique ecological adaptations facilitating DMSP degradation within the sediment microenvironment.

Of particular note is the identification of the dddP gene within Acinetobacter calcoaceticus, a gene encoding a pivotal enzyme that catalyzes the cleavage of DMSP to release DMS. This genetic confirmation unequivocally demonstrates that enzymatic pathways responsible for DMS production are actively operative in the Cochin Estuary sediments. This is a vital link connecting microbial community structure to functional outcomes impacting the marine sulfur flux and atmospheric chemistry on a regional scale.

The implications of these findings extend beyond mere academic interest, offering potential applications in environmental biotechnology. The ability of bacteria such as Acinetobacter calcoaceticus and Bacillus cereus to metabolize organic sulfur compounds efficiently suggests possibilities for bioengineering approaches aimed at mitigating sulfur emissions or remediating volatile sulfur pollutants in aquatic environments. This biotechnological angle places the research at the interface of microbial ecology and applied environmental management.

Furthermore, the study establishes an essential baseline dataset for the Cochin Estuary—a tropical system previously missing from global sulfur cycle models. Understanding the spatial-temporal variability of DMSP production and degradation is fundamental for refining biogeochemical models that predict how coastal ecosystems modulate atmospheric sulfur loads, cloud formation, and hence, climate feedback loops. This research paves the way for integrating tropical estuarine dynamics into global climate modeling frameworks.

The researchers advocate for future investigations employing multi-omics approaches such as metagenomics and metatranscriptomics to elucidate the complete suite of DMSP degradation pathways and their regulatory mechanisms across varied spatial scales and seasonal regimes. Such integrative molecular techniques would enable a more nuanced understanding of microbial functional diversity and activity, improving predictive capabilities regarding the estuary’s role in global sulfur cycling.

Conclusively, this landmark study spotlights the interplay between estuarine microbiology, ecosystem biogeochemistry, and climate science. It uncovers the profound influence of microbial metabolism in a dynamic tropical estuary, reinforcing the significance of localized natural processes informing global environmental phenomena. As monsoon-driven climatic variability intensifies under global change scenarios, the insights gained here underscore the urgency of monitoring and preserving these critical coastal interfaces.

In summary, the Cochin Estuary research signifies an essential stride in marine biochemical research by documenting the first comprehensive mapping of DMSP-degrading bacterial communities and their enzymatic functions in an Indian tropical estuarine system. From identifying novel microbial players to delineating environmental controls on sulfur fluxes, the study enriches our understanding of the ocean’s role in climate regulation and invites interdisciplinary collaborations aiming to harness microbial functions for environmental sustainability.


Subject of Research:
Dimethylsulfoniopropionate (DMSP) degradation by marine bacteria in the Cochin Estuary and its implications for global sulfur cycling and climate regulation.

Article Title:
Dimethylsulfoniopropionate (DMSP) Degradation by Marine Bacteria along the Cochin Estuarine System

Web References:
http://dx.doi.org/10.2174/0118740707433988260408095129

References:
Divakaran D, Sujatha C.H, Mathew D.E. Dimethylsulfoniopropionate (DMSP) Degradation by Marine Bacteria along the Cochin Estuarine System. Open Biotechnol. J., 2026; 20: e18740707433988.

Keywords:
DMSP, dimethylsulfide, marine bacteria, sulfur cycle, Cochin Estuary, estuarine microbiology, monsoon, climate regulation, biogeochemical cycling, microbial enzymatic pathways, γ-Proteobacteria, Firmicutes

Unlocking Fungal Secrets: From Spider Silk to Scientific Discovery

3 June 2026 at 15:54

In a groundbreaking exploration of the subtle intricacies woven into agricultural ecosystems, recent scientific research has unveiled an extraordinary role for spider webs as natural, non-invasive reservoirs of fungal life. This pioneering study, conducted by a team from Thammasat University alongside collaborators at Thailand’s National Center for Genetic Engineering and Biotechnology (BIOTEC), delves into the largely unappreciated function of spider orb webs in capturing and preserving living fungal communities. This discovery not only challenges conventional sampling methodologies but also opens new avenues for biodiversity assessment and environmental microbiology.

Spider webs, especially those constructed by the orb-weaving species Cyclosa mulmeinensis, were traditionally studied for their architectural marvel and predatory function, yet they stand out as natural particulate collectors in agroecosystems. This particular species is famed for its “trashline” decorations—linear arrays of assorted environmental debris including vegetation fragments, insect remnants, and dust particles—which inadvertently act as adhesive traps for airborne biological entities. The researchers hypothesized that these intricate silk matrices could be exploited to isolate and culture viable fungi, thus providing a non-destructive sampling platform to study microbial biodiversity in paddy fields.

The setting for this investigation was the tropical rice agroecosystems of Thailand, with webs harvested from embankments across multiple provinces including Pathum Thani, Nakhon Nayok, and Phetchaburi. Employing meticulous sterile collection techniques, the team ensured that the fungal samples obtained were not contaminated by external sources. Once the web material was transferred to laboratory conditions, researchers successfully cultured 112 fungal isolates. This process, unlike molecular DNA sampling that may detect dead or fragmented organisms, prioritized the recovery of living fungi, thus allowing for detailed phenotypic and genotypic assessments.

The diversity uncovered was remarkable. Isolates spanned 23 taxa within six fungal genera, notably Alternaria, Aspergillus, Cladosporium, Fusarium, Penicillium, and Talaromyces. Each of these genera holds ecological and agricultural significance, ranging from plant pathogens to beneficial decomposers. Intriguingly, certain genetic lineages, especially in Cladosporium and Talaromyces, showed no matches in existing genetic databases, indicating potential new species or cryptic diversity that have yet to be documented. This revelation underscores the webs’ potential as untapped reservoirs of microbial novelty.

One of the most compelling facets of this work is the demonstration that fungal propagules intercepted on spider silk retain viability to an extent that permits culturing. This crucial finding offers a methodological advantage over conventional techniques often reliant on environmental DNA analysis. DNA-based detection methods, while comprehensive in breadth, cannot discriminate between dormant, dead, or viable organisms. In contrast, culturing permits the isolation of active fungal cells, facilitating downstream experimentation including pathogenicity tests, resistance profiling, and ecological functional studies.

Conventional fungal biodiversity monitoring typically involves soil, air, and plant tissue sampling, or molecular-based surveys. These procedures may prove logistically demanding, invasive, or insensitive to viable organism status. By harnessing the natural particle-retentive capacity of spider webs, this innovative method introduces a supplementary, low-impact tool capable of continuous environmental sampling as spiders rebuild their webs. Because only fragments of webs were collected, the spiders themselves were unharmed, ensuring an ethical balance between scientific inquiry and ecological preservation.

Beyond the practical implications for microbial ecology, the study brings to the fore a hidden dimension of biodiversity surveillance. The notion that a seemingly ephemeral, delicate structure such as a spider web can harbor and maintain viable microbial assemblages is profound. It challenges assumptions about the limits of biological sampling surfaces and highlights everyday natural structures as rich, overlooked archives of microscale life.

This research also has far-reaching implications for agriculture. Rice fields, vital food-producing ecosystems, are vulnerable to pathogens and ecological imbalances caused by microbial factors. The ability to non-destructively monitor fungal populations via spider webs could enable earlier disease detection, inform integrated pest management strategies, and contribute to sustainable farming. Moreover, unraveling previously undocumented fungal diversity may lead to novel biotechnological or agricultural applications.

While this initial study focused on a single spider species within specific geographic regions, the principle it elucidates promises broader applicability. The universal adhesive properties of spider silk and the widespread presence of orb-weaving spiders in various ecosystems suggest that spider webs could be systematically employed to survey microbial diversity across diverse habitats globally. Further research will be crucial to optimize sampling protocols, characterize seasonal and spatial variations, and explore correlations with environmental factors.

The natural lifecycle of spider webs, characterized by periodic dismantling and reconstruction, provides a dynamic temporal dimension to sampling. This cyclical renewal means webs can continuously accumulate freshly airborne particles and associated fungi, making them living archives and potential indicators of temporal changes in microbial community composition. The adaptability and ubiquity of spider webs thus position them as potent natural biosensors for environmental monitoring.

Dr. Thanakron Into, the lead student researcher, underscores the transformative potential of this approach, emphasizing that spider webs themselves act as subtle yet intricate biological samplers. The study bridges biology and materials science, showing how engineered silk properties extend beyond prey capture to encompass ecological monitoring capabilities. This synergy between form and function exemplifies nature’s inherent ingenuity and its relevance to modern scientific challenges.

Ultimately, the revelation that something as common as a spider’s web can yield vast reservoirs of living fungal diversity reframes our understanding of microhabitat complexity. It compels scientists, ecologists, and agronomists alike to broaden their investigative horizons and reconsider how we tap into the hidden biodiversity around us. As research advances, spider webs could become vital tools in the continuous quest to document, understand, and preserve the microscopic players crucial to ecosystem health and resilience.


Subject of Research: Fungal biodiversity sampling using spider webs in agricultural ecosystems
Article Title: Spider webs as reservoirs of culturable fungal diversity: evidence from orb-weaving Cyclosa mulmeinensis spider in Thai rice agroecosystems
News Publication Date: 20-Apr-2026
Web References:

  • Biodiversity Data Journal: https://bdj.pensoft.net/article/187035/
  • DOI: http://dx.doi.org/10.3897/BDJ.14.e187035
    References: Thanakron Into et al., 2026, Biodiversity Data Journal
    Image Credits: Thanakron Into et al., 2026
    Keywords: spider silk, fungal diversity, microbial ecology, orb-weaving spider, Cyclosa mulmeinensis, agricultural ecosystems, biodiversity monitoring, culturable fungi, environmental sampling, rice fields, fungal isolation, tropical agroecosystems

Inside Meta's attempts to play catch-up with AI

A year after Mark Zuckerberg installed Alexandr Wang to jolt Meta’s artificial intelligence efforts into wartime mode, the $1.5 trillion company has produced Muse Spark, its most credible AI model yet.

By handing responsibility for Meta’s AI revival to a then-28-year-old start-up founder rather than a veteran researcher, Zuckerberg bet that an outsider’s urgency and ambition could succeed where the company’s established AI organisation had struggled.

According to interviews with current and former Meta employees, and associates of Wang, the billionaire wunderkind has now begun to eke out results, while navigating criticism over his experience, early research challenges and the esoteric internal politics of working at a Big Tech behemoth.

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Tesla found new buyers for its Cybertruck: Kazakh emergency services

3 June 2026 at 03:33

Kazakhstan’s Ministry of Emergency Situations has confirmed it will purchase additional Tesla Cybertrucks after the electric pickup proved effective in rescue operations in Almaty, the country’s largest city.

The Central Asian country has become the latest small international market to adopt the Cybertruck, as Tesla continues to struggle with collapsing domestic demand for the electric pickup.

more…

Tesla’s own AI trainers don’t trust ‘Full Self-Driving’ or its safety stats, Reuters finds

28 May 2026 at 14:33

A major Reuters investigation published today reveals that Tesla’s widely touted “Full Self-Driving” safety statistics are built on deeply flawed methodology — and that the company’s own data labelers, the workers who train the AI system, don’t trust the technology to drive them.

The report, based on interviews with nine former Tesla data labelers, a former self-driving engineer, and 11 traffic-safety researchers, paints a damning picture of the gap between Tesla’s safety marketing and the reality of its autonomous driving program.

more…

Tesla (TSLA) and SpaceX merger would be Musk’s 4th billion-dollar self-deal

27 May 2026 at 10:30

Elon Musk is reportedly floating the idea of merging Tesla (TSLA) and SpaceX, just weeks before SpaceX’s massive IPO on the Nasdaq. If it happens, this would literally be the fourth time Musk has orchestrated a billion-dollar transaction between companies he controls.

No one in corporate America is doing this at the scale Musk is. Between SolarCity, Twitter/X, and xAI, Musk has built a playbook for self-dealing that is unprecedented — and now he’s gearing up for the biggest one yet.

more…

Musk abandoned his own ‘solar electric economy’ to burn gas for an AI chatbot no one uses

25 May 2026 at 15:54

Elon Musk spent years telling the world that solar power was the obvious answer to Earth’s energy needs — that a small patch of desert could power the entire United States. Now, he’s burning millions of tons of fossil fuels to run an AI chatbot that has lost 60% of its downloads, selling the unused compute to a company he called “misanthropic and evil” three months ago, and pitching space-based solar panels right as SpaceX files for a $2 trillion IPO.

The contradictions are stacking up faster than xAI’s unpermitted gas turbines.

more…

Did CMS discover an unexpected quasiparticle? New search observes what looks to be ‘toponium’

15 April 2025 at 00:04

While searching for new Higgs bosons the CMS experiment at the Large Hadron Collider (LHC) may have just found a surprise. They have observed an excess of events that look to be a new particle, and are reporting high statistical evidence for their claim. The only question is what exactly is this new particle?

The search was initially designed to look for new, heavier, versions of the Higgs boson decaying to a top quark and an anti-top quark. Its well known that the Higgs boson of the Standard Model, discovered jointly by ATLAS and CMS in 2012, underlies the mechanism which gives all fundamental particles their masses. The Higgs boson itself interacts with particles in proportion to their mass, preferring heavier particles over lighter ones. It therefore interacts the most strongly with the heaviest known fundamental particle, the top quark, which has a mass of ~173 GeV. The Higgs boson itself only has a bass of 125 GeV, meaning conservation of energy dictates it can’t decay into a top quark-antiquark pair.

However many theories of physics beyond the the Standard Model predict additional Higgs bosons, heavier cousins of the current one. If these new heavy Higgs bosons had a mass larger than 350 GeV, they would likely decay to a top quark-antiquark pair quite often. CMS therefore was analyzed its data searching for this signature, hoping to find signs of a new Higgs boson. To do so, they had scrutinize very carefully the known production of top quark-antiquark pairs, which are produced copiously at the LHC from other processes. If a new particle was being produced and decaying to top quarks, the mass of the new particle would give the top quarks a characteristic energy. One key sign of a new particle would therefore be an excess of top quark-antiquark events at a particular energy, corresponding to the mass of the new particle. 

When CMS scrutinized their data looking for such an excess they found one. But curiously right ~350 GeV, the minimum energy required to produce the top quark-antiquark pair. It would be quite the coincidence for a new particle to show up right at this minimum threshold, which made CMS consider alternative possibilities.

 

 

A comparison of the observed CMS data and their estimate of backgrounds as a function of the invariant mass of the top quark antiquark system. CMS observes an excess of events at ~350 GeV, which is well fit with a toponium model (red line).

 One unorthodox explanation that seems to fit the bill is ‘toponium’, a short lived bound state of the top quark-antiquark pair is being formed. Toponium would be the heaviest version of ‘quarkonia’ we have seen, bound states of quark antiquark pairs that form bound states similar to atoms. We have observed and measured quarkonia states of the other quarks for decades, however it was long thought that the top quark, whose large mass causes it to decay in just 10^(-25) seconds, would decay too quickly to create observable bound state effects at a hadron collider. Toponium production would happen most often if the top quarks were produced just at the energy threshold, such that they don’t any extra energy. These low energy top quarks would spend more time close to each other than normal, rather than immediately flying away, so they could have time to briefly form a toponium state before decaying. However, once small hints of intriguing excesses started appearing in LHC analyses, updated calculations in the last few years suggested that perhaps such an effect could be observable.

These calculations are approximate, and more work is still being done to refine them. But the preliminary predictions they give for the properties of toponium seem to match well with what CMS is seeing, both in terms of the rate of toponium production and the quantum properties of the toponium state (spin and parity).

Still CMS is being cautious before claiming a discovery of toponium. They claim observation of an ‘excess at the top quark pair production threshold’ which is consistent with toponium. However given the limited present data and incomplete theoretical models of toponium, they cannot rule out that the excess they are seeing is coming from a new Higgs-like particle.

CMS measurement of the cross section of the two different hypothetical particles
CMS measurement tries to disentangle the quantum properties of the observed excess. The x-axis shows the estimated rate of production a ‘pseudoscalar’ particle producing the excess. The y-axis shows a similar estimate for a ‘scalar’ particle. The allowed region for the scalar still includes zero, while the zero pseudoscalar hypothesis is clearly excluded at larger than 5 standard deviations.

Further work will be needed to develop improved theoretical models of toponium, and detailed studies from CMS assessing the properties of their observed excess. The excess will also need confirmation from CMS’s rival LHC experiment, ATLAS, to ensure it has not merely made a mistake in its analysis.

However, the smart money would say this very likely looks like toponium. Which, while not signaling the long sought overthrow of the standard model, would be an unexpected and cool surprise from the LHC. Understanding the properties of this previously-thought-impossible quasiparticle will spawn much fruitful research in the years to come. Physicists love a surprise!

Paper:

“Observation of a pseudoscalar excess at the top quark pair production threshold” https://arxiv.org/abs/2503.22382

Additional CMS Paper considering Heavy-Higgs interpretation “Search for heavy pseudoscalar and scalar bosons decaying to top quark pairs in proton-proton collisions

Read more

CERN Courier “CMS observes top–antitop excess

Symmetry Magazine “Don’t call it toponium

Discloure: The author is a member of the CMS collaboration but did not directly work on this analysis

Erratum 4/15/2025 : The article was updated to clarify that in the theory literature prior to the LHC toponium was thought possible to form, just that it was thought to be too small an effect to be observable. The article previously incorrectly stated it had been previously thought impossible to form

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