Physicists Detect Mysterious X Particles in 'Primordial Soup' For The First Time

The first particle to be detected in the primordial soup is thought to have existed just after the Big bang.

In a medium called the quark-gluon plasma, created in the Large Hadron Collider by colliding lead ion. Physicists were able to tease out 100 of the exotic particles known as X particles.

"This is just the beginning of the story," says physicist Yen-Jie Lee of MIT, who is a member of the international CMS Collaboration.

We have shown we can find a signal. We want to use the quark-gluon plasma to probe the X particle's internal structure, which could change our view of what kind of material the universe should produce.

The very early Universe was not made of the same stuff that we see today. For a few millionths of a second, it was filled with particles called quarks and gluons. The quark-gluon plasma is what it is.

The particles came together in less time than it takes to blink. The particles in the quark-gluon plasma came apart in different configurations after a brief collision.

We don't know how a particle is put together in one of those configurations. This is the X particle, and it's only been seen very rarely and briefly in particle colliders.

Physicists have been creating small flashes of quark-gluon plasma in particle accelerators for a long time. This could give a better chance to understand them.

Positively charged atoms of lead were slammed together at high speeds. Each of the 13 billion crashes produced a shower of particles. It's a huge amount of data to sift through.

The production of X particles should be enhanced because there are so many quarks and gluons. People thought it would be hard to find them because there are so many other particles in the quark soup.

When X particles decay, they produce a shower of lower-mass particles. The team developed a method to recognize the patterns of X particle decay. They fed the data into their software.

The signal at the specific mass was identified by the algorithm and indicated the presence of around 100 X particles in the data. This is a good start.

"It's almost unthinkable that we can tease out these 100 particles from this huge dataset," Lee said.

The data is insufficient to learn more about the X-particle's structure, but the discovery could bring us closer. Now that we know how to find the X-particle's signature, teasing it out in future data sets should be a lot easier. The more data we have, the easier it will be to understand them.

Three quarks make up the protons and neutrons. Physicists believe that there is a new kind of X particle made from two mesons that contain two quarks. It will decay more slowly if it's the former, because it's more tightly bound.

We don't have enough statistics yet, so our data is consistent with both. In the next few years, we will take more data so we can separate the two scenarios.

"That will help us understand the particles that were produced in the early Universe."

The research has been published.