Yi Liu

In an accelerator, particles collide, and for a fleeting instant a D meson is born — a particle that lives for less time than it takes light to cross a grain of sand. It promptly shatters into lighter fragments: a kaon, a lepton, and a neutrino.

In a particle accelerator in Beijing, an anti-Lambda hyperon, a rare antimatter particle, slams into an ordinary proton. Instead of simply disappearing, they transform into a whole bouquet of other particles: a positively charged kaon, two pions, and sometimes additional neutral pions. Such transformations for the anti-Lambda had never been observed before.

In a particle accelerator, the anti-lambda particle is a rare guest. It is born on the fly, lives for a tiny fraction of a second, and usually decays on its own. But sometimes it manages to collide with an ordinary proton, and then a whole shower of light particles is born: kaons, pions.

In the BEPCII accelerator, electrons and positrons collide, producing billions of particles. Among them is the J/ψ meson, which lives for less than a billionth of a second. Its decay sometimes yields an eta meson (ηc), an even shorter-lived clump of quarks.

A superconductor carries current without loss, like a perfectly smooth road where cars glide with no friction. But what if you scatter rocks and potholes across that road? Scientists decided to find out by adding disorder to a superconducting material just one atom thick.

The J/psi particle lives for an instant and then decays into lighter particles, much like a snapped string scattering into pieces. Physicists from the BESIII collaboration caught over ten billion such decays to figure out exactly what 'pieces' are produced.

When a particle decays, it doesn't just vanish: it transforms into a whole set of other particles, and each transformation has its own script. Physicists from the BESIII collaboration have, for the first time, broken down the rare decay of the D0 meson step by step: it turns into two kaons and two pions.

A woven basket made of willow twigs holds its shape thanks to the interweaving. A similar pattern, triangles linked into a flat network, has been found in a new crystal with the formula Cs₃V₉Te₁₃. Here, vanadium atoms form two sets of triangles that pierce each other like threads in fabric. This pattern is not just pretty: it forces electrons to move along special "flat" energy pathways.

Every second, billions of decays happen inside our bodies, and nobody notices. But physicists do: they smash particles in accelerators and watch what fragments they fly into. Hidden in those fragments is the answer to why we exist at all. Right after the Universe was born, there were equal amounts of particles and antiparticles, but today all we see around us is particles.

Imagine a balance scale with identical weights, yet one pan always tips lower. In the world of elementary particles, this imbalance is called CP violation: particles and their mirror twins (antiparticles) behave slightly differently.

The charmed particle D+ lives for a tiny fraction of a second before breaking apart into lighter particles, like an overloaded bridge losing its supports. Physicists at the BESIII collider caught millions of such decays and sorted them out. In one decay mode, four pions and an eta meson are produced. The probability of this event turned out to be higher than expected: about 3 chances in 1000.

Quarks are the tiny building blocks that make up protons and neutrons. Usually, they stick together in pairs: a particle and its mirror-image antiparticle. But sometimes quarks form more exotic combinations, which physicists call exotic states.

The dance floor is packed with people, each moving on their own. Suddenly, some of them break into pairs (spinning around, barely noticing their neighbors) while the rest line up in chains. That's roughly how atoms behave in the metal CsCr₃Sb₅, a member of the kagome metals, whose crystal lattice resembles a woven basket.

A stone falls into a pond, and ripples spread across the water. Long waves and short ones travel at the same speed: that's how ordinary sound behaves in almost any medium. But in quantum liquids, things can be different. Physicists considered a superfluid where particles move along a "flat" energy band.

Imagine trying to overhear a whisper between two people in a noisy hall. That's roughly the challenge physicists face when they want to understand how electrons pair up inside a superconductor. And if the "hall" is also squeezed by a giant press to pressures of hundreds of thousands of atmospheres, the task seems impossible. The authors of the new study found an ingenious solution.

An archaeologist carefully brushes away layer after layer, and each new stratum at the charmonium dig is a rare decay captured by the detector. Charmonium — a bound state of a charm quark and its antiquark — lives for mere fractions of a second, yet it manages to tell us about the forces that hold quarks together.