• Quarks are elemental particles, with no sub-structure. Understanding them is crucial to learning how physics works on the smallest levels.
  • By studying collisions of incredibly small particles made up of quarks known as J/psi particles, scientists were better able to understand matter on a fundamental nature.
  • Measuring the J/psi particles, Florida State scientists found results that contradicted earlier studies at CERN.

Quarks are one of the fundamental parts of all matter. They're particles that combine together to form what are known as hadrons, some of which are protons and neutrons—the basic components of atomic nuclei. Studying photons in order to better understand quarks, scientists at Florida State University have made the first-ever measurements of a subatomic particle known as the J/psi particle, which is created out of the energy in the photon-proton collisions.

Some quick background: Both quarks and photons are elementary particles, meaning that they're subatomic particles. So they don't have any sub-structure themselves; they simply just ... exist. Protons, meanwhile, are composite particles, meaning they're compromised of two or more elementary particles. So the scientists wanted to make photons collide with a composite particle like a proton to learn about how particles function.

"It's really cool to see," says Assistant Professor of Physics Sean Dobbs in a press statement. "This is opening up a new frontier of physics."

Dobbs compares his team's experiments to an extremely small car crash. To create their crash, they used the GlueX Spectrometer at the Thomas Jefferson National Accelerator Facility in Virginia. The team blasted a photon beam into spectrometer, and the beam then passed through a canister of liquid hydrogen and reacted with protons in the nucleus of the canister's hydrogen atoms.

While the scientists weren't able to capture these tiny reactions and collisions as they happened, they worked backwards. They established what happened when the beam went through the canister, with approximately one to two million gigabytes of data per year to help them.

The J/psi particle, first discovered independently by two separate groups in 1974, is made up of a pair of quarks: one charm quark and one anti-charm quark. There are six types of quarks. The most common are known as "up" and "down" quarks, which make up protons and neutrons. Charm quarks are (comparatively) heavier than these, and have only a brief lifespan before decaying into more conventional particles. The J/psi particle was the first chance to prove that the so-called "quark model" accurately described nature.

By studying the J/psi particle in these collisions, the team was able to look at production of other charm quark-containing subatomic particles. They found more J/psi particles than they expected.

That means that gluonic structure (the gluons that can make protons) is a big contributor to the mass of the proton structure. In fact, according to the scientists, gluons directly contribute more than 80 percent of the mass of the protons studied. Understanding how gluons contribute to protons gives scientists are a clearer picture of the fundamental nature of matter.

The findings challenge other studies from the CERN collider in Switzerland earlier this year, which detected short-lived particles known as pentaquarks that the FSU team didn't find. Particle physics is complex stuff, but amidst the car crash of photons and gluons and quarks, scientists get closer to understanding the complexity of existence.

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David Grossman

David Grossman is a staff writer for PopularMechanics.com. He's previously written for The Verge, Rolling Stone, The New Republic and several other publications. He's based out of Brooklyn.