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Higgs-boson properties clarified through decay pattern analysis

The ATLAS collaboration finds evidence of Higgs-boson decays to muons and improves sensitivity to Higgs-boson decays to a Z boson and a photon.

Studies of the properties of the Higgs boson featured prominently in the program of the major annual physics conference, the 2025 European Physical Society Conference on High Energy Physics (EPS-HEP), held this week in Marseille, France. Among the results presented by the ATLAS collaboration were two results narrowing in on two exceptionally rare Higgs-boson decays.

The first process under study was the Higgs-boson decay into a pair of muons (H→μμ). Despite its scarceness—occurring in just 1 out of every 5,000 Higgs decays—this process provides the best opportunity to study the Higgs interaction with second-generation fermions and shed light on the origin of mass across different generations. Up to now, the interactions of the Higgs boson with have only been observed for particles from the third, heaviest, generation: the tau lepton and the top and bottom quarks.

Can the Large Hadron Collider snap string theory?

In physics, there are two great pillars of thought that don’t quite fit together. The Standard Model of particle physics describes all known fundamental particles and three forces: electromagnetism, the strong nuclear force, and the weak nuclear force. Meanwhile, Einstein’s general relativity describes gravity and the fabric of spacetime.

However, these frameworks are fundamentally incompatible in many ways, says Jonathan Heckman, a at the University of Pennsylvania. The Standard Model treats forces as dynamic fields of particles, while general relativity treats gravity as the smooth geometry of spacetime, so gravity “doesn’t fit into physics’s Standard Model,” he explains.

In a recent paper in Physical Review Research, Heckman, Rebecca Hicks, a Ph.D. student at Penn’s School of Arts & Sciences, and their collaborators turn that critique on its head. Instead of asking what string theory predicts, the authors ask what it definitively cannot create. Their answer points to a single exotic particle that could show up at the Large Hadron Collider (LHC). If that particle appears, the entire string-theory edifice would be, in Heckman’s words, “in enormous trouble.”

Cheap Catalyst Turns Acids Into Pharmaceutical Gold

Carboxylic acids are common components in bioactive compounds and serve as widely available building blocks in organic synthesis. When transformed into carboxy radicals, these acids can initiate the formation of valuable carbon-carbon and carbon-heteroatom bonds, a key step in the creation of new materials and pharmaceutical agents. Despite their utility, few existing methods rely on cost-effective catalysts.

Addressing this gap, a team from WPI-ICReDD and the University of Shizuoka developed a straightforward hydrogen atom transfer (HAT) strategy that selectively converts carboxylic acids into carboxy radicals. This method employs xanthone, a commercially available and inexpensive organic ketone, as the photocatalyst. The study was recently published in the Journal of the American Chemical Society.

The KATRIN experiment sets new constraints on general neutrino interactions

Neutrinos are elementary particles that are predicted to be massless by the standard model of particle physics, yet their observed oscillations suggest that they do in fact have a mass, which is very low. A further characteristic of these particles is that they only weakly interact with other matter, which makes them very difficult to detect using conventional experimental methods.

The KATRIN (Karlsruhe Tritium Neutrino) experiment is a large-scale research effort aimed at precisely measuring the effective mass of the electron anti-neutrino using advanced instruments located at the Karlsruhe Institute of Technology (KIT) in Germany.

The researchers involved in this experiment recently published the results of a new analysis of data from the second measurement campaign in Physical Review Letters, which set new constraints on interactions involving neutrinos that could arise from unknown physics that is not explained by the standard model, also known as general neutrino interactions.

New method replaces nickel and cobalt in battery for cleaner, cheaper lithium-ion batteries

A team of McGill University researchers, working with colleagues in the United States and South Korea, has developed a new way to make high-performance lithium-ion battery materials that could help phase out expensive and/or difficult-to-source metals like nickel and cobalt.

The team’s breakthrough lies in creating a better method of producing “disordered rock-salt” (DRX) cathode particles, an alternative battery material. Until now, manufacturers struggled to control the size and quality of DRX particles, which made them unstable and hard to use in manufacturing settings. The researchers addressed that problem by developing a method to produce uniformly sized, highly crystalline particles with no grinding or post-processing required.

“Our method enables mass production of DRX cathodes with consistent quality, which is essential for their adoption in and renewable energy storage,” said Jinhyuk Lee, the paper’s corresponding author and an Assistant Professor in the Department of Mining and Materials Engineering.

“Australia Just Changed Batteries Forever”: Quantum Tech Unleashed With 1,000 Times the Life, Leaving Global Energy Giants Reeling in Shock

A quantum battery operates on the principles of quantum mechanics, diverging from traditional batteries which rely on ion flow for charging and discharging. In quantum batteries, energy is stored by moving electrons into higher energy states with photons acting as charge carriers. During charging, photons transfer their energy to electrons, enabling storage.

Key quantum properties, such as entanglement and superabsorption, are harnessed to enhance the charging rate. Entanglement allows particles to function cohesively during the charging or discharging process, while superabsorption increases the energy storage capacity, leading to higher energy densities. Despite their theoretical potential and scalability, practical quantum batteries have faced challenges, with existing prototypes unable to sustain energy beyond a few nanoseconds.

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Quantum objects’ dual nature mapped with new formula for ‘wave-ness’ and ’particle-ness‘

Since its development 100 years ago, quantum mechanics has revolutionized our understanding of nature, revealing a bizarre world in which an object can act like both waves and particles, and behave differently depending on whether it is being watched.

In recent decades, researchers exploring this have learned to measure the relative “wave-ness” and “particle-ness” of quantum objects, helping to explain how and when they veer between wave-like or particle-like behaviors.

Now, in a paper for Physical Review Research, researchers at the Stevens Institute of Technology report an important new breakthrough: a simple but powerful formula that describes the precise closed mathematical relationship between a quantum object’s “wave-ness” and “particle-ness.”

Speed test of ‘tunneling’ electrons challenges alternative interpretation of quantum mechanics

As the traveled along the waveguide and tunneled into the barrier, they also tunneled into the secondary waveguide, jumping back and forth between the two at a consistent rate, allowing the research team to calculate their speed.

By combining this element of time with measurements of the photon’s rate of decay inside the barrier, the researchers were able to calculate dwell time, which was found to be finite.

The researchers write, “Our findings contribute to the ongoing tunneling time debate and can be viewed as a test of Bohmian trajectories in . Regarding the latter, we find that the measured energy–speed relationship does not align with the particle dynamics postulated by the guiding equation in Bohmian mechanics.”

Carefully tuned laser beam protects quantum spins from noise

Researchers have discovered a simple yet powerful way to protect atoms from losing information—a key challenge in developing reliable quantum technologies.

By shining a single, carefully tuned on a gas of atoms, they managed to keep the atoms’ internal spins synchronized, dramatically reducing the rate at which information is lost. In quantum sensors and , atoms often lose their —or “spin”—when they collide with each other or the walls of their container.

This phenomenon, known as spin relaxation, severely limits the performance and stability of such devices. Traditional methods to counteract it have required operating in extremely low magnetic fields and using bulky magnetic shielding.