At CERN’s Large Hadron Collider (LHC), scientists have made an incredible discovery about the early universe. They created a trillion-degree “soup” of particles called quarks and gluons that resembles liquid more than gas. This primordial soup existed for a tiny fraction of a second after the Big Bang and is vital to understanding how matter developed.
This plasma is made up of quarks and gluons that fused to form protons and neutrons, the building blocks of atoms. By speeding up heavy lead atoms and smashing them together, researchers can recreate this quark-gluon plasma for fleeting moments. This helps them glimpse into the conditions of our universe’s infancy.
Recently, a team from MIT, led by physicist Yen-Jie Lee, observed how quarks behave in this plasma. They found that as quarks move through the plasma, they create “wakes,” similar to how a boat creates ripples in water. This marks a significant step forward, showing that the quark-gluon plasma acts not just as a fluid but behaves like a true liquid.
Lee noted, “The plasma is incredibly dense, able to slow down a quark and produce splashes like a liquid.” This finding helps clarify long-standing questions about the early universe.
Using the LHC’s Compact Muon Solenoid (CMS) detector, Lee’s team developed a method to measure the size and speed of these wakes. Understanding these properties will enrich our knowledge of quark-gluon plasma and the early universe’s dynamics.
Interestingly, this primordial soup isn’t just the first liquid; it’s also the hottest liquid ever created, with temperatures soaring into the trillions of degrees. It closely resembles a “near-perfect liquid” with seamless flow, unlike many other fluids.
The research also ties to various theories and models, including the hybrid model, which predicts specific behaviors of quark-gluon plasma. Significant attention is placed on this plasma as it provides insights into the fundamental forces of nature.
While making discoveries, scientists must navigate obstacles, such as the challenges of detecting quark wakes. Lee’s team innovatively focused on quarks paired with a neutral particle called a Z-boson. This pairing allows researchers to see the effects of a single quark in the plasma without interference from other quarks.
After analyzing billions of collisions, they identified instances where Z-bosons interacted with quarks. In these cases, quarks left detectable wakes, confirming the fluid dynamics expected from the hybrid model. Lee stated, “We’ve gained the first direct evidence that the quark drags more plasma with it as it travels.” This breakthrough could pave the way for deeper studies into the properties of this unique state of matter.
This research, published in the journal Physics Letters B, opens a window into our universe’s most enigmatic periods. It adds to the idea that the universe began as a hot, dense soup which eventually cooled and formed everything we know today.
