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. <\/p>\n
The discovery, reported by the STAR collaboration at Brookhaven National Laboratory in New York, involved high-energy proton collisions inside the lab\u2019s Solenoidal Tracker detector. Researchers detected rare quark-antiquark pairs created from the vacuum itself rather than from the colliding protons. <\/p>\n
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.<\/p>\n
Measuring vacuum signatures<\/p>\n
Quantum chromodynamics, the established theory of the strong force that binds quarks<\/a> 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.<\/p>\n 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.<\/p>\n 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<\/a> called hyperons.<\/p>\n The STAR team discovered key evidence in the form of the particles\u2019 quantum property of spin. Quarks and antiquarks born from the vacuum carry correlated spins\u2014a 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.<\/p>\n