Collider Performs

So far, the elusive particles, called extra-heavy strange baryons, haven't been seen directly, but they are leaving tantalizing hints of their existence.

These extra-heavy strange baryons may be freezing out other subatomic particles in a plasma soup of subatomic particles that mimics conditions in the universe a few moments after the Big Bang, nearly 14 billion years ago. 

Primordial soup

The particles were created during an experiment conducted inside the Relativistic Heavy Ion Collider (RHIC), an atom smasher at Brookhaven National Laboratory in Upton, New York. 

There, scientists created a soupy concoction of unbound quarks — the subatomic particles that make up protons and neutrons — and gluons, the tiny particles that bind quarks together and carry the strong nuclear force. 

Physicists think this quark-gluon plasma is similar to the primordial soup that emerged milliseconds after the universe was born.

Using the RHIC, physicists are trying to understand how quarks and gluons initially came together to form protons, neutrons and other particles that are categorized as hadrons. 

"Baryons, which are hadrons made of three quarks, make up almost all the matter we see in the universe today," study co-author and Brookhaven theoretical physicist Swagato Mukherjee, said in a statement.

Elusive matter

But while ordinary baryons are ubiquitous throughout the universe, the Standard Model — the physics theory that explains the bizarre world of subatomic particles — predicts the existence of a separate class of baryons made up of heavy or ''strange" quarks. 

These heavy baryons would exist only fleetingly, making them hard to spot.

If extra-heavy baryons did exist, they should leave some trace behind, scientists say.

Enter the RHIC experiment, which accelerates gold nuclei, or the protons and neutrons in a gold atom, to nearly the speed of light, and then crashes these gold ions into one another. 

The resulting collisions can raise the temperature inside the collider to a mind-boggling 7.2 trillion degrees Fahrenheit (4 trillion degrees Celsius), or 250,000 times as hot as the heart of the sun. 

The huge burst of energy released during the collision melts the protons and neutrons in the nuclei into their smaller components, quarks and gluons.

By combining their measurements with a mathematical model of quarks and gluons interacting in a 3D lattice, the team was able to show that extra-heavy strange baryons were the most plausible explanation for the RHIC's experimental results.  Read More: