Scientists have made a groundbreaking discovery in nuclear physics, measuring the heaviest nucleus ever recorded to decay via proton emission. This achievement marks the first time such a feat has been accomplished in over 30 years, with the previous record set in 1996.

The research team from the University of Jyväskylä, Finland, successfully produced and measured the lightest known isotope of astatine, 188At, consisting of 85 protons and 103 neutrons. This exotic nucleus was created through a complex process involving a fusion-evaporation reaction and identified using a sophisticated detector setup.

“The properties of this nucleus reveal a trend change in the binding energy of the valence proton,” explains Doctoral Researcher Henna Kokkonen, who led the study. “This could be explained by an interaction unprecedented in heavy nuclei.”

The research team’s findings have significant implications for our understanding of atomic nuclei and their behavior. By expanding a theoretical model to interpret the measured data, scientists can now better comprehend the intricate mechanisms governing these complex systems.

Kokkonen notes that studying such exotic nuclei is extremely challenging due to their short lifetimes and low production cross sections. However, precise techniques like those employed in this study have made it possible to unlock new insights into the fundamental nature of matter.

The research article was published in Nature Communications as part of an international collaboration involving experts in theoretical nuclear physics. This breakthrough discovery not only pushes the boundaries of human knowledge but also has far-reaching implications for our understanding of the universe and its mysteries.

The Large Hadron Collider (LHC), a 17-mile particle accelerator buried under the French-Swiss border, has achieved the centuries-old dream of alchemists: transforming lead into gold. However, this accomplishment was not without its limitations – it happened within a fraction of a second. The scientists reported their results in Physical Reviews.

The achievement was made possible by the sophisticated and sensitive detector called ALICE, which is roughly the size of a McMansion. It was scientists from the University of Kansas, working on the ALICE experiment, who developed the technique that tracked “ultra-peripheral” collisions between protons and ions that resulted in gold creation at the LHC.

According to Daniel Tapia Takaki, professor of physics and leader of KU’s group at ALICE, these ultra-peripheral collisions involve near misses between particles. The ions racing around the LHC tunnel are heavy nuclei with many protons, each generating powerful electric fields. When accelerated, these charged ions emit photons – they shine light.

“When you accelerate an electric charge to near light speeds, it starts shining,” Tapia Takaki said. “One ion can shine light that essentially takes a picture of the other. When that light is energetic enough, it can probe deep inside the other nucleus, like a high-energy flashbulb.”

During these ultra-peripheral collisions, surprising interactions can occur, including the creation of gold through photon-photon collisions. These events are incredibly clean, with almost nothing else produced. They contrast with typical collisions where sprays of particles flying everywhere.

However, the ALICE detector and the LHC were designed to collect data on head-on collisions that result in messy sprays of particles. These clean interactions were hard to detect with earlier setups.

Tapia Takaki’s KU co-authors on the paper are graduate student Anna Binoy; graduate student Amrit Gautam; postdoctoral researcher Tommaso Isidori; postdoctoral research assistant Anisa Khatun; and research scientist Nicola Minafra. The KU team at the LHC ALICE experiment plans to continue studying the ultra-peripheral collisions.

Tapia Takaki said that while the creation of gold fascinated the public, the potential of understanding the interactions goes deeper. This light is so energetic, it can knock protons out of the nucleus, sometimes one, sometimes two, three or even four protons. We can see these ejected protons directly with our detectors.

Each proton removed changes the elements: One gives thallium, two gives mercury, three gives gold. These new nuclei are very short-lived, they decay quickly, but not always immediately. Sometimes they travel along the beamline and hit parts of the collider – triggering safety systems.

That’s why this research matters beyond the headlines. With proposals for future colliders even larger than the LHC – some up to 100 kilometers in Europe and China – you need to understand these nuclear byproducts. This ‘alchemy’ may be crucial for designing the next generation of machines.

This work was supported by the U.S. Department of Energy Office of Science, Office of Nuclear Physics.

The search for dark matter has been ongoing for nearly a century, with scientists trying various methods to detect this invisible substance. Despite numerous attempts, very little is known about its fundamental properties. However, researchers believe that if a nuclear clock is developed, it could finally unmask dark matter’s influence on visible matter.

Physicists in Germany and Colorado made a breakthrough last year by using the radioactive element thorium-229 to build a potential nuclear clock. When Prof. Gilad Perez’s theoretical physics group at the Weizmann Institute of Science learned of this achievement, they recognized an opportunity to advance the search for dark matter even before a fully functional nuclear clock becomes a reality.

The team proposed a novel method for detecting dark matter’s influence on properties of the thorium-229 nucleus. They hypothesized that minute deviations in the absorption spectrum of thorium-229 could reveal dark matter’s effect, allowing them to study its properties.

Calculations showed that the new measurements could detect dark matter’s influence even if it were 100 million times weaker than gravity. The researchers also calculated how different dark matter models would affect thorium-229’s absorption spectrum, hoping this will ultimately help determine which models are accurate and what dark matter is actually made of.

While laboratories around the world continue to refine the measurement of thorium-229’s resonance frequency, a process expected to take years, the development of a nuclear clock could revolutionize many fields, including Earth and space navigation, communications, power grid management, and scientific research.

A thorium-229-based nuclear clock would be the ultimate detector for dark matter, enabling researchers to detect incredibly slight deviations in its ticking, which could reveal dark matter’s influence. The European Research Council (ERC) recently awarded an ERC Advanced Grant to Prof. Perez’s group to support the continued development of this line of research.

In conclusion, the search for dark matter continues, and a nuclear clock may finally unmask its influence on visible matter. While the journey ahead will be long and challenging, researchers remain hopeful that their efforts will ultimately reveal the secrets of this mysterious substance.