Lifeboat Foundation

A long-standing prediction of quantum electrodynamics is that high-energy photons can scatter off each other. However, this process has yet to be observed because dedicated experiments have an extremely low signal-to-noise ratio. Now Alexander Macleod at the Extreme Light Infrastructure, Czech Republic, and Ben King at the University of Plymouth, UK, have designed an experiment that could achieve a high-enough signal-to-noise ratio to measure the phenomenon [1]. Researchers could use such measurements to derive the values of fundamental constants in quantum electrodynamics and then set constraints on various extensions to the standard model of particle physics.

Conventionally, scientists have looked for evidence of photon–photon scattering by colliding pairs of laser beams. Macleod and King instead propose colliding three laser beams: an x-ray beam and two high-power optical beams. The two optical beams provide the photons that scatter off each other, and the x-ray beam imparts a momentum kick to the scattered photons. This kick alters the trajectory of the photons and spatially separates them from much of the experimental background. As a result, in the detection region, the signal-to-noise ratio is higher than that of two-beam setups.

Macleod and King consider how their setup could be realized in two currently existing research facilities: the European X-Ray Free-Electron Laser facility in Germany, as part of the planned BIREF@HIBEF experiment, and the SPring-8 Angstrom Compact Free Electron Laser in Japan. They then show how the technology used in these facilities should be sufficient to measure photon–photon scattering. Macleod says that such a demonstration would be important for researchers working on “high-power lasers, strong-field physics, and quantum electrodynamics.”

Gravitational-wave signals from black hole mergers could reveal the presence of “gravitational atoms”—black holes surrounded by clouds of axions or other light bosons.

Subrahmanyan Chandrasekhar famously stated that black holes are “the most perfect macroscopic objects there are in the Universe: The only elements in their construction are our concepts of space and time.” His observation relates to the fact that astrophysical black holes, as described by the Kerr spacetime, can be characterized by just two parameters: mass and spin. However, things might get more complex. Theorists have predicted that if a bosonic field interacts with a Kerr black hole, perturbations in the field can grow to form a cloud around the black hole, creating a “gravitational atom,” in which the bosons surrounding the black hole behave somewhat like the electrons surrounding an atomic nucleus [1] (Fig. 1). What’s more, if such a gravitational atom is part of a binary involving a second black hole, excitations and ionization processes akin to those occurring in hydrogen atoms may affect how the black hole binary evolves.

University of Nebraska–Lincoln researchers have achieved a breakthrough in antiferromagnetic spintronics, a development that could expand the nanotechnology’s capabilities, which have been limited by their need for excessive power.

Deep inside what we perceive as solid matter, the landscape is anything but stationary. The interior of the building blocks of the atom’s nucleus—particles called hadrons that a high school student would recognize as protons and neutrons—are made up of a seething mixture of interacting quarks and gluons, known collectively as partons.

In a paper published in Physical Review Letters this week, physicists from Amsterdam and Copenhagen argue that close observations of merging black hole pairs may unveil information about potential new particles. The research combines several new discoveries made by UvA scientists over the past six years.

In 2023, the ATLAS collaboration, which provided its first W boson mass measurement in 2017, released an improved measurement based on a reanalysis of proton–proton collision data from the first run of the LHC. This improved result, 80,366.5 MeV with an uncertainty of 15.9 MeV, lined up with all previous measurements except the CDF measurement, which remains the most precise to date, with a precision of 0.01%.

The CMS experiment has now contributed to this global endeavor with its first W boson mass measurement. The keenly anticipated result, 80,360.2 with an uncertainty of 9.9 MeV, has a precision comparable to that of the CDF measurement and is in line with all previous measurements except the CDF result.

“The wait for the CMS result is now over. After carefully analyzing data collected in 2016 and going through all the cross checks, the CMS W mass result is ready,” says outgoing CMS spokesperson Patricia McBride. “This analysis is the first attempt to measure the W mass in the harsh collision environment of the second running period of the LHC. And all the hard work from the team has resulted in an extremely precise W mass measurement and the most precise measurement at the LHC.”

Some recent dark matter experiments have begun employing levitated optomechanical systems. Kilian et al. explored how levitated large-mass sensors and dark matter research intersect.

Levitated sensors are quantum technology platforms that use magnetic fields, electric fields, or light to levitate and manipulate particles, which become very sensitive to weak forces. These sensors are especially well suited for detecting candidates in regimes where current large-scale experiments suffer limitations, such as ultralight and certain hidden-sector candidates.

The authors discussed how these advantages make levitated sensors, including optically trapped silica nanoparticles, magnetically trapped ferromagnets, and levitated superconducting particles, ideal for detecting different dark matter candidates.

Question Can microplastics reach the olfactory bulb in the human brain?

Findings This case series analyzed the olfactory bulbs of 15 deceased individuals via micro-Fourier transform infrared spectroscopy and detected the presence of microplastics in the olfactory bulbs of 8 individuals. The predominant shapes were particles and fibers, with polypropylene being the most common polymer.

Meaning The presence of microplastics in the human olfactory bulb suggests the olfactory pathway as a potential entry route for microplastics into the brain, highlighting the need for further research on their neurotoxic effects and implications for human health.

Glycoproteins are a diverse group of proteins that have carbohydrate chains covalently attached to their polypeptide chains. These carbohydrate chains, or glycans, can vary greatly in size, complexity, and composition, leading to a wide range of glycoprotein functions and properties.

The attachment of glycans to proteins typically occurs in two main types of linkages: N-linked glycosylation, where the carbohydrate is attached to the nitrogen atom of asparagine side chains, and O-linked glycosylation, where it attaches to the oxygen atom of serine or threonine side chains. These modifications can significantly impact a glycoprotein’s structure, stability, and function.