Sunday, November 15, 2026

Matter–antimatter asymmetry still provides no evidence of new physics

The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

Differences between matter and antimatter were investigated in beauty mesons decays. — image:
Proton–proton collisions at the LHC produce, among other particles, mesons containing beauty and strange quarks and antiquarks. Differences between matter and antimatter were investigated in their decays into secondary particles.
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Credit: Source: IFJ PAN

The Universe's dominance by ordinary matter is compelling evidence that matter and antimatter are not perfect reflections of each other. However, known differences do not explain the scale of this imbalance, leaving open the possibility that unknown physics is responsible. A new analysis of meson decays, conducted by the LHCb collaboration, has narrowed the scope of the search for such a scenario while paving the way for more precise measurements in the future.

Over the past decade, scientists working at the Large Hadron Collider have focused their efforts on searching for differences between particles of matter and antimatter produced in proton-proton collisions. The latest and exceptionally thorough analysis of data collected between 2016 and 2018 as part of the LHCb experiment was carried out by a team of physicists from the universities of Warwick, Manchester and Oxford in the UK, TU Dortmund University in Germany, and the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow.

The motivation behind this research lies in what is arguably the most astonishing feature of our world: the fact that it... simply exists. Why is this so surprising? Because, in its present form, it should not exist – at least according to our current understanding of physics. Cosmological models suggest that, shortly after the Big Bang, equal amounts of matter and antimatter must have been produced in the Universe. Yet when a particle meets its antiparticle, both are converted into energy in a process known as annihilation. Meanwhile, our reality is clearly dominated by particles of matter that have escaped annihilation. The worlds of matter and antimatter particles therefore cannot have been – and still are not – perfectly symmetrical.

“In many physical processes, simultaneously replacing all particles with their antiparticles and inverting all spatial coordinates leaves the laws governing these phenomena unchanged. This principle is known as charge-parity symmetry, or CP symmetry. We have been searching for processes that violate this symmetry in the decays of particles produced in proton–proton collisions at the LHC, specifically in the decays of mesons containing beauty and strange quarks and antiquarks,” explains Dr. Agnieszka Dziurda (IFJ PAN), an expert in the physics of these decays.

The Standard Model, a theoretical framework developed in the 1970s, describes the elementary particles and their interactions. According to this model, matter is made up of elementary particles known as fermions. These include quarks (down, up, strange, charm, beauty and top) and leptons (electrons, muons, tau leptons and their associated neutrinos). In addition, every type of matter particle has a corresponding antiparticle.

Each proton–proton collision at the LHC produces a large number of massive, short-lived particles. In earlier studies of CP violation, physicists have observed asymmetries in certain decay processes involving particles and antiparticles. However, these phenomena alone cannot account for the present-day dominance of matter. Now, in a paper published in the renowned journal Physical Review Letters, researchers have presented an analysis of the decays of Bs0 mesons. These mesons decay into lighter particles, and the Standard Model allows scientists to calculate the expected frequency of a given decay process and compare these predictions with experimental data.

“Interestingly, we chose to investigate a process in which the Standard Model predicts no asymmetry at all. So why study it at all?” asks Dr. Dziurda. She explains: “Because if an asymmetry were nevertheless observed, it could be a signal that previously unknown physics was at work. We also know that current theoretical predictions for the probabilities of certain beauty-meson decay channels differ significantly from the values obtained experimentally. This discrepancy could, for example, stem from theoretical effects that have not yet been fully accounted for in our calculations. At this stage, however, we cannot rule out the possibility that it points to physics beyond the Standard Model.”

Beauty mesons were exceptionally well suited to the search for CP symmetry breaking for another reason. They possess a remarkable property: they oscillate extremely rapidly between states corresponding to matter (a strange quark paired with a beauty antiquark) and antimatter (a beauty quark paired with a strange antiquark). One of the earlier measurements by the LHCb experiment showed that these oscillations can occur several trillion times per second. Thanks to such fast oscillations, the analysis could be carried out without having to determine the initial state of each meson.

A particular challenge for researchers was to thoroughly understand and characterise detector asymmetries, that is, differences in the detection of particles and antiparticles arising from the detector itself. This is because positively and negatively charged particles curve in opposite directions as they travel through the detector's magnetic field. Because detection efficiencies vary across the detector, this can affect the numbers of recorded particles and antiparticles. Such effects can produce an apparent asymmetry in the data even when the process being studied occurs with equal probability for particles and antiparticles. To account for these effects, the researchers used extensive calibration samples and computer simulations, and regularly reversed the direction of the detector's magnetic field. Corrections for differences in particle and antiparticle detection efficiencies were also applied when determining the final asymmetry in beauty-meson decays.

“We had to make sure that any asymmetry observed in the data, however small, was not caused by the detector itself. This was a crucial aspect of the entire analysis because, given the precision of our measurement, detector-related effects could have been of the same magnitude as the asymmetry we were looking for,” says Dr. Dziurda.

The data from the LHCb experiment analysed in this study revealed a difference of approximately one to two cases per thousand decays. However, since the measurement uncertainty was larger than the observed effect, the result is consistent with the predictions of the Standard Model. Although the finding does not solve the mystery of the missing antimatter or rule out the existence of new physics, it narrows down the range of possibilities in which new phenomena might be hiding. In the decays studied, any unknown process that would cause an asymmetry greater than about 2% would almost certainly have been detected.

Future research, using the larger datasets already collected with the upgraded LHCb detector, will allow scientists to investigate even more subtle effects in the discussed meson decays. Should a new source of CP violation be hidden therein, the analysis presented here provides physicists with a clearer understanding of where – and precisely how – the search should be conducted.

The Polish contribution to the research was funded by a grant awarded by the Polish Ministry of Science and Higher Education.

The Henryk Niewodniczański Institute of Nuclear Physics (IFJ PAN) is currently one of the largest research institutes of the Polish Academy of Sciences. A wide range of research carried out at IFJ PAN covers basic and applied studies, from particle physics and astrophysics, through hadron physics, high-, medium-, and low-energy nuclear physics, condensed matter physics (including materials engineering), to various applications of nuclear physics in interdisciplinary research, covering medical physics, dosimetry, radiation and environmental biology, environmental protection, and other related disciplines. The average yearly publication output of IFJ PAN includes over 600 scientific papers in high-impact international journals. Each year the Institute hosts about 20 international and national scientific conferences. One of the most important establishments of the Institute is the Bronowice Cyclotron Centre (CCB), which is an infrastructure unique in Central Europe, serving as a clinical and research centre in the field of medical and nuclear physics. In addition, IFJ PAN runs four accredited research and measurement laboratories. IFJ PAN is a member of the Marian Smoluchowski Kraków Research Consortium: “Matter-Energy-Future”, which in 2012-2017 enjoyed the status of the Leading National Research Centre (KNOW) in physics. In 2017, the European Commission granted the Institute the HR Excellence in Research award. As a result of the categorization of the Ministry of Education and Science, the Institute has been classified into the A+ category (the highest scientific category in Poland) in the field of physical sciences.

SCIENTIFIC PUBLICATIONS:

“First Measurement of the Decay-Time-Integrated CP Asymmetry in Bs0→Ds–π+ Decays”

LHCb Collaboration

Physical Review Letters 2026, 137, 081802

DOI: 10.1103/ljtv-y278

LINKS:

http://www.ifj.edu.pl/

The website of the Institute of Nuclear Physics, Polish Academy of Sciences.

http://press.ifj.edu.pl/

Press releases of the Institute of Nuclear Physics, Polish Academy of Sciences.

IMAGES:

IFJ261112b_fot01s.jpg

HR: http://press.ifj.edu.pl/news/2026/11/12/IFJ261112b_fot01.jpg

Proton–proton collisions at the LHC produce, among other particles, mesons containing beauty and strange quarks and antiquarks. Differences between matter and antimatter were investigated in their decays into secondary particles. (Source: IFJ PAN)

Journal

Physical Review Letters

DOI

10.1103/ljtv-y278

Article Title

First Measurement of the Decay-Time-Integrated CP Asymmetry in Bs0→Ds–π+ Decays

Environmental steroid hormones in aquatic ecosystems: biogeochemical processes, mixture risks, and sustainable management

A new review maps how steroid hormones move, transform and persist in water — and why removing parent compounds alone may not remove the risk

Innovation Press

image:
Steroid hormones enter and persist in waters via wastewater, manure runoff, and airborne particles.
Conjugated forms and transformation products can be missed, while mixtures can amplify pollution risks.
These pollutants can disrupt reproduction in aquatic life and may pose broader risks to human health.
Monitoring, source control, and nature-based treatment provide a sustainable path forward.
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Credit: Yang H., Feng Q., Tang Y., et al. (2026). Environmental steroid hormones in aquatic systems: Biogeochemical dynamics, mixture risks, and sustainable mitigation. The Innovation Water 1:100015. https://doi.org/10.59717/j.tiw.2026.100015

Every day, wastewater treatment plants, livestock farms and manure-fertilized fields release steroid hormones into rivers, lakes and coastal seas. The amounts are tiny — often measured in nanograms per liter — but for fish and other aquatic species, tiny is enough. Decades of research have linked these compounds to shifted sex ratios, impaired reproduction and population decline in fish. A new review in The Innovation Water argues that the usual way of tracking them — measuring a handful of parent compounds before and after treatment — understates both exposure and risk.

The review, led by Hang Yang and Yi Zhang of the Institute of Hydrobiology, Chinese Academy of Sciences, with Lei Wang of Shenzhen Polytechnic University, walks through the full life cycle of environmental steroid hormones: where they come from, where they go, what they do, and what can be done about them.

One central finding concerns what standard monitoring misses. Steroid hormones rarely travel as free, parent compounds alone. Conjugated forms excreted in urine can be deconjugated by microbes in the environment, regenerating active hormones; transformation products can retain or even gain biological activity. In some secondary wastewater effluents, the review notes, conjugated and halogenated estrogens together can account for 60–70% of the total molar load of steroid estrogens — fractions invisible to targeted assays focused on parent compounds.

Real waters also carry mixtures: natural hormones, synthetic analogues, transformation products and other co-contaminants such as microplastics and antibiotics. Mixture effects may be additive, synergistic or antagonistic, yet risk assessment frequently evaluates compounds one at a time. Evidence of harm is strongest for aquatic life — vitellogenin induction, skewed sex ratios, reduced fecundity — while direct epidemiological evidence linking environmental exposure to human health outcomes remains limited, a boundary the authors state explicitly.

On the treatment side, the review's message is equally cautious. Conventional processes lower parent-compound concentrations but vary with compound, process conditions and season. Sorption and membrane separation may simply relocate pollutants to sludge or concentrate streams; advanced oxidation can destroy parent structures without achieving full mineralization, leaving active transformation products. The authors argue that removal rates for parent compounds should not be compared across technologies without context, and that treatment should be judged by whether transformation products, residual endocrine activity and overall toxicity decline together.

Their proposed path forward is organized under a One Health framework: expand monitoring to wastewater, manure, agricultural runoff, receiving waters, sediments and indicator organisms; bring mixture effects into risk assessment; control sources from pharmaceutical use and disposal to livestock operations; and combine engineered treatment with nature-based solutions such as constructed wetlands and microalgae systems. Whether any of it works, the review concludes, should be verified by measurable, simultaneous declines in exposure, residual endocrine activity and toxicity — not by parent-compound removal rates alone.

###

Yang H., Feng Q., Tang Y., et al. (2026). Environmental steroid hormones in aquatic systems: Biogeochemical dynamics, mixture risks, and sustainable mitigation. The Innovation Water 1:100015. https://doi.org/10.59717/j.tiw.2026.100015

DOI

10.59717/j.tiw.2026.100015

Method of Research

Systematic review

Subject of Research

Not applicable

Article Title

Environmental steroid hormones in aquatic systems: Biogeochemical dynamics, mixture risks, and sustainable mitigation

Archaeologists shed new light on wealth and status among Europe's early herders

A new study by researchers from the University of Copenhagen and the Max Planck Institute indicates that early herding communities in Central Europe only gradually developed social inequality – it was not imported by the steppe migrants

University of Copenhagen

Artistic reconstruction of young girl with copper neck ring — image:
Artistic reconstruction of the young girl with the copper neck ring (and hair spirals) in grave 41 at Čachovice. Red ochre face paint inspired by decorations on the pottery in her grave.
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Credit: Oil pastel by Solveig Chaudesaigues-Clausen

How unequal were prehistoric societies? And how can archaeologists measure wealth in cultures that left behind no written records, no tax registers and no census data?

A researcher from the University of Copenhagen has developed a multi-proxy method called QuantWealth that uses archaeological evidence from graves to reconstruct social status, wealth display, and inequality thousands of years ago.

In a new study published in Journal of Neolithic Archaeology, the method was applied to almost 300 4-5,000-year-old graves in present-day Bohemia. The researchers compared the analyses of the graves with genetic ancestry and Y-chromosome patterns of the skeletal remains to track paternal lineages, including pathologies, age, and gender to give unprecedented detail to the story of the so-called Corded Ware culture.

The researchers found that social inequality emerged gradually in Bohemia over several centuries following migrations from the steppe. These migrations spread early Indo-European dialects across Europe, but, at least in Bohemia, inequality was not deeply entrenched:

"Archaeologists have long debated whether steppe populations migrating across Europe from Ukraine brought with them a highly unequal social system and patriarchy. Our results suggest a much more dynamic picture, where social differences developed gradually. Achieving status through life-actions appears to have been more important than through inheritance, at least during the first 400 years", says University of Copenhagen archaeologist Mikkel Nørtoft, main author of the study, who developed the QuantWealth method in his PhD thesis.

A society in transition
Mikkel Nørtoft and his colleague Adam B. Rohrlach analysed 296 burials from the Corded Ware culture in Bohemia dating between approximately 2,900 and 2,300 BCE.

“Following a few harsh years of “dark sun” clouded by a devastating volcanic eruption 2,900 BCE, the earliest herder communities, settling in Bohemia around 2,900-2,700 BCE, seem to have focused mostly on building social cohesion across this new network of migrants in Central Europe. In Bohemia, they did this through shared burial rituals, and building earthen mounds, but with few grave goods”, Mikkel Nørtoft explains.

Wealth differences were small, mostly age-related, and power seems to have been distributed across multiple steppe-derived lineages, with little gender inequality.

Increased competition and inequality
Over time, circa 2,700-2,500 BCE, however, funerary competition in Bohemia intensified after a new lineage appeared. The researchers found increasing concentrations of prestige items, meat offerings, expanding exchange networks, and growing gender inequality. Adult men in particular became associated with more richly furnished graves, and younger adults became most frequent in the graves, but without clearly increasing signs of violence in skeletal trauma.

“In the final phase, roughly 2,500-2,300 BCE, we see a few rich displays of family wealth through children, and the previously new lineage now dominated the burial record. So maybe the new lineage had gained the most followers and power through the competitive burial parties, and their descendants were now competing among themselves”, Mikkel Nørtoft points out and adds:

“The few rich child graves and this prevailing lineage could indicate more inherited wealth and emerging traits of persistent inequality. Ethnographic parallels could also support the idea that parents adorned their children with ornaments to increase their social value in future marriage exchange. Brides often moved into the husband’s household in Corded Ware societies, and bridewealth or dowry is preserved in early Indo-European vocabulary, and historically common in Indo-European societies.”

This could be exemplified in one particularly rich female child grave in this late phase from the site Čachovice, the richest among all Bohemian graves in the study. This grave also included an extremely rare copper neck ring, a widespread upper-class symbol (known as “torcs”) in the later European Bronze and Iron Ages.

According to the researchers, these developments suggest growing social competition and the possible emergence of more durable forms of inequality among late Corded Ware communities.

Whether this development shows the first small steps to long-standing family dynasties documented later in the Bronze Age will require more data on both the Corded Ware Culture and the related Bell Beaker Culture who replaced them in Central Europe.

“We now have a correlation between changing Y-haplogroup lineages and unequal burial wealth display in one region, but we need more DNA data to confirm this at the family level, and elsewhere”, explains Nørtoft. The study also shows how combining DNA, archaeology, and language can enrich narratives about social changes in the past.

The study “Cooperation and Competition: Changes in Wealth, Power, and Patrilines in the Czech Corded Ware Culture” has been published in Journal of Neolithic Archaeology.

Contact
Archaeologist postdoc Mikkel Nørtoft
University of Copenhagen and National Museum of Denmark
Email: mnoertoft@palaeome.org

Geneticist postdoc Adam B. Rohrlach
Department of Archaeogenetics
Max Planck Institute for Evolutionary Anthropology
E-mail: adam.rohrlach@adelaide.edu.au

The research was funded by Independent Research Fund Denmark and the European Research Council.

About QuantWealth
The QuantWealth method addresses a longstanding challenge in archaeology: how do researchers compare wealth and status across large numbers of prehistoric burials.

Instead of simply counting grave goods, which has been the preferred method, QuantWealth combines multiple indicators associated with social investment and prestige. These include the number and exclusivity of grave goods, the labour required to produce them, access to long-distance exchange networks, evidence of feasting and the effort invested in constructing graves.

Together, these factors allow researchers to estimate how wealth and status were expressed within ancient communities.

The researchers then combine these archaeological indicators with advanced statistical analyses to map patterns of wealth and social differentiation through time.

The Corded Ware Culture
The Corded Ware Culture was one of the most widespread archaeological cultures of prehistoric Europe, spanning large parts of northern, central and eastern Europe between approximately 2900 and 2300 BCE. It is named after the distinctive pottery decorated with impressions made by twisted cords.

Corded Ware communities practiced a mixed economy based on animal husbandry, farming, and are associated with the spread of people carrying ancestry from the East European steppe and the spread of Indo-European languages across Eurasia.

Individual burials with characteristic grave goods, such as “battle-axes” in male graves, cord-decorated beakers and amphoras, and dogtooth ornaments in female graves, are a hallmark of the culture.

DOI

10.12766/jna.2026.7

Method of Research

Data/statistical analysis

Article Title

Cooperation and Competition: Changes in Wealth, Power, and Patrilines in the Czech Corded Ware Culture

Article Publication Date

10-Nov-2026

Early radiocarbon dates (range midpoints) for the Corded Ware culture incl. potential “proto-Corded Ware” in Southern Poland, data from Bourgeois et al. 2025, adapted and edited by Mikkel Nørtoft.

Credit

Illustration: Mikkel Nørtoft

SOCIOBIOLOGY

Curiosity and fearlessness apparent in German Shepherd genes

Uppsala University

image:
Meeting ‘ghosts’ is one part of the Dog Mentality Assessment test (DMA) that the dogs in the study underwent.
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Credit: Voichita Marinescu

German Shepherd dogs bred for working are more curious and less neurotic than German Shepherds bred for show. A new study from Uppsala University and the Swedish University of Agricultural Sciences has shown that the differences are not only apparent in the dogs’ behaviour, but also in their genes. In previous studies, similar genes in humans have been associated with neuroticism.

A German Shepherd dog’s behaviour is very important because they are used as working dogs, for example in the police force or in the defence forces. Breeding dogs with the right traits can be difficult and costly. But with a better understanding of the genetics underlying such traits, breeding can be improved.

In a new study, ethologists and geneticists worked together to investigate how the behaviour of German Shepherd dogs is reflected in their genes. They have shown that the German Shepherd population in Sweden is comprised of two groups: one bred primarily for their appearance and the other bred for functional roles as working dogs.

“Breeders of working dogs have selected and bred the ones that really enjoy working; it’s a bit like a game for them. It’s interesting that we can now see that this selective breeding has indeed led to differences between working dogs and show dogs among German Shepherds – differences that can be seen at both the behavioural and genetic levels,” says Kerstin Lindblad-Toh, Professor of Comparative Genomics at Uppsala University and one of the study’s leaders.

Investigated German Shepherd behaviour and genetics

To measure behaviour in German Shepherd dogs, a standardised behaviour test called the Dog Mentality Assessment (DMA) was used where the dogs were confronted with a variety of situations. The DMA tests how dogs react to an invitation to play, threatening ghost-like figures, and being handled by a stranger. Today, the majority of German Shepherds in Sweden are tested using the DMA. In the study, the researchers looked at data from around 23,000 German Shepherd dogs.

“We could see that, on average, the working dogs showed less fear, more curiosity and were able to socialise well with humans. This shows how important it is to select for behaviour when selecting dogs for breeding for important functional roles in our community,” says Åke Hedhammar, Professor Emeritus at the Swedish University of Agricultural Sciences.

The researchers then took blood samples from 373 German Shepherd dogs who had undergone the DMA to be able to map their genomes.

“We could then see that there were areas in the genome where differences could be seen in the dogs depending on how curious or playful they were, for example. That meant that we were able to identify some of the genes in working dogs that are linked to curiosity and playfulness,” says Kerstin Lindblad-Toh.

In humans too, researchers have also found links between genes and behaviour. Some of the genes that have now been linked to the behaviour of German Shepherd dogs have been associated in previous studies with neuroticism in humans.

“It’s interesting that several of the genes that we identified as influencing behaviour in German Shepherds are also linked to that behaviour in humans. So we now have an example of how we might also acquire more knowledge about different behaviours in people with help of dogs in the long term,” says Kerstin Lindblad-Toh.

Bigger studies in the pipeline with the Swedish Armed Forces

Behaviour is not just controlled by individual genes: it is a complex interaction between many different genes. In collaboration with the Swedish Armed Forces, the researchers are now going to proceed with bigger studies in order to better map the genetics of behaviour.

“That would ultimately mean that these findings could be used to select which dogs have the best prospects of becoming good working dogs and which could be used in breeding. But we are not there yet. This study is just a first step and shows that there are actually clear differences in behaviour between working German Shepherd dogs and German Shepherd show dogs,” Åke Hedhammar says.