World-first: Scientists observe particles emerging from nothing in collider

IE (By Chris Young; Apr 9, 2026) -- The STAR collaboration tracked rare quark-antiquark pairs created in proton collisions, offering new evidence that empty space is not truly empty.

Scientists at the Relativistic Heavy Ion Collider have observed particles emerging directly from empty space for the first time, confirming a long-standing prediction of quantum chromodynamics. 

A collision inside the STAR detector at the Relativistic Heavy Ion Collider (Brookhaven National Laboratory)

The discovery, reported by the STAR collaboration at Brookhaven National Laboratory in New York, involved high-energy proton collisions inside the lab’s Solenoidal Tracker detector. Researchers detected rare quark-antiquark pairs created from the vacuum itself rather than from the colliding protons. 

The finding provides the clearest evidence yet that matter can materialize from what classical physics considers empty space. As such, it could help provide an answer to one of the biggest mysteries in physics: how particles acquire mass.

Measuring vacuum signatures

Quantum chromodynamics, the established theory of the strong force that binds quarks inside protons and neutrons, holds that a perfect vacuum is not empty. It contains constant fluctuations known as virtual particles, including short-lived quark-antiquark pairs.

Under ordinary conditions, these pairs appear and vanish almost instantly. When sufficient energy is supplied, however, the theory predicts they can become real particles with measurable mass.

In the STAR experiment, proton collisions generated a cascade of particles. As free quarks cannot exist in isolation, quarks produced from the vacuum immediately combine into composite particles called hyperons.

The STAR team discovered key evidence in the form of the particles’ quantum property of spin. Quarks and antiquarks born from the vacuum carry correlated spins—a shared alignment imprinted at creation. This correlation survived as the quarks formed hyperons and persisted even after the hyperons decayed in less than a tenth of a billionth of a second.

Detection of these spin-aligned hyperons allowed the team to trace the quarks’ origin to the vacuum rather than to the original collision debris. “This is the first time we’ve seen the whole process,” Zhoudunming You, a member of the STAR collaboration, explained in an interview with New Scientist.

Shedding light on the origin of particle mass

The result has an important bearing on one of physics’ central puzzles: the origin of particle mass.

Quantum chromodynamics predicts that quarks gain most of their mass through interactions with the vacuum, yet the precise mechanism behind this has remained unclear. The new observation provides a direct experimental handle on those vacuum interactions.

It is worth noting that the results are not yet definitive, as researchers must rule out other factors that may have caused the signal. Future runs at the Relativistic Heavy Ion Collider, and complementary experiments at other facilities, will aim to refine these findings.

Still, the new research opens a new experimental route to study vacuum properties and the mass-generation process predicted by quantum chromodynamics. The STAR collaboration’s work marks the first direct observation of vacuum-derived matter and sets the stage for further tests of the theory at the energy frontier.