Meson facts for kids

Mesons are tiny particles, smaller than atoms! They're made of two even tinier pieces: a quark and an antiquark. An antiquark is like an opposite version of a quark. Quarks and antiquarks have something called "spin." When they come together, their spins can cancel out. This makes mesons similar to another particle called a Higgs boson.

The word "meson" comes from a Greek word meaning "middle." This is because when mesons were first found, their weight (or mass) was in between very light particles (like electrons) and heavier particles (like protons).

What Makes Mesons Special?

Mesons belong to a family of particles called hadrons. This just means they are made of smaller particles called quarks. Since quarks can have different electric charges, mesons can also have a charge. However, sometimes the charges of the quark and antiquark cancel out, making a meson with no charge.

Another family of hadrons are called baryons. Baryons are made of three quarks. All quarks have a "spin" of 1/2. When three quarks combine, their spins never add up to a whole number (like 0, 1, or 2). Particles with spins that are not whole numbers are called Fermions. Fermions follow special rules, meaning only one fermion can be in the same spot at the same time. All known baryons and quarks are fermions.

Mesons are different! They are made of one quark and one antiquark. Even though each has a spin of 1/2, when they combine, their spins can add up to a whole number (like 0 or 1). Particles with whole number spins are called bosons. Bosons follow different rules. More than one boson can actually be in the same spot in space at the same time! So, all mesons are bosons. This can be a bit tricky to understand because the quarks inside a meson cannot be in the same spot, but the meson itself can.

How Mesons Are Made

The most common natural way we find mesons is when cosmic rays (tiny, super-fast particles from space) crash into matter. Scientists can also create mesons in special machines called particle accelerators. These machines smash high-energy quarks and antiquarks together.

However, mesons don't last very long. They are very unstable and quickly change into other particles. Mesons that have an electric charge can decay into electrons and neutrinos. Mesons with no charge can decay into photons (particles of light). When a meson decays, the matter and antimatter inside it destroy each other. This creates a lot of energy, following Einstein's famous equation, E=mc².

See also

In Spanish: Mesón para niños