What Drives the Acceleration?
A team from Fudan University has identified a previously unknown force influencing the most extreme state of matter in the Universe. The quark-gluon plasma produced when atomic nuclei collide at nearly light speed accelerates most intensely at its outer boundary, where a sudden drop in pressure triggers rapid outward expansion. The finding gives researchers a new parameter for probing matter under the rules of quantum chromodynamics and may help interpret results from the RHIC and LHC colliders.
Inside the Quark-Gluon Plasma
Collisions of atomic nuclei at velocities close to the speed of light create quark-gluon plasma, the hottest state of matter ever observed. In this state, quarks and gluons move without confinement, a condition reminiscent of the Universe in its earliest moments after the Big Bang. To study this behavior, the scientists ran two computer models simulating particle collisions at energies ranging from 3.5 gigaelectronvolts up to 2.76 teraelectronvolts.
According to their results, the strongest acceleration happens near the plasma's outermost edge. There, pressure falls sharply, causing the material to expand outward at high speed. Co-author Xu-Guang Huang says that this acceleration may set key properties of matter interacting under quantum chromodynamics.
“Such acceleration could determine the characteristics of matter subject to the laws of quantum chromodynamics.” – Xu-Guang Huang
The effect may influence phase transitions in matter and the alignment of particle spins. The next step is to refine the models and look for observable traces of this acceleration in experimental data. Beyond explaining long-puzzling results from RHIC and LHC, this line of research could deepen our understanding of the fundamental forces that shape the Universe, including the conditions created by the Big Bang and the formation of matter. It may also open avenues for future technologies in energy and materials science.