Scientists have synthesized an isotope of the superheavy element livermorium using a novel fusion reaction. The result paves the way for the discovery of new chemical elements.

How and where in the Universe are the chemical elements created? How can we explain their relative abundance? What is the maximum number of protons and neutrons that the nuclear force can bind in a single nucleus? Nuclear physicists and chemists expect to find answers to such questions by creating and studying new elements. But as elements get more and more massive, they become harder and harder to synthesize. The heaviest elements discovered so far were created by bombarding high-atomic-number (high-Z) actinide targets with beams of calcium-48 (⁴⁸ Ca). This isotope is particularly suited to such experiments because of its peculiar nuclear configuration, in which the number of neutrons and protons are both “magic numbers.” Yet this approach could not produce elements beyond oganesson (proton number, Z = 118).

A new method for studying the behavior of multiparticle systems relies on a simple “head count” of particles in imaginary boxes.

One way to characterize the interactions in a bacterial colony or a polymer mixture is to trace the path of individual particles through the system, but such tracking can become difficult when the particles are indistinguishable. Researchers have developed a new method that extracts particle dynamics from a simple counting of particles in imaginary boxes of adjustable size [1]. They demonstrated this “countoscope” strategy in experiments with small plastic spheres moving around in a liquid. The measured rate of diffusion was different for different sized boxes, which revealed particle clumping. The countoscope’s ability to identify such collective behavior could one day help researchers understand the mechanisms that cause bacteria and other life forms to group together.

Biologists, chemists, and soft-matter physicists often study many-particle systems in which the particles shuffle around each other in a “random walk.” A useful measure of this behavior is the diffusion constant, which describes how fast an individual particle moves. A measurement of the diffusion constant can tell a biologist whether cells are healthy or sick, or it can tell a chemist how fast a molecule will move through a gel in a chemical-analysis device. The diffusion constant is typically determined by following the path of a single particle in a video recording. This trajectory reconstruction becomes difficult, however, when the particles are numerous and all look the same, says Sophie Marbach from Sorbonne University in France.