Standard Model

The Standard Model reveals an underlying organization to the universe

Using the framework of quantum field theory, it structures all known particles into 12 matter particles, alongside five particles that carry three of the four fundamental forces. Although remarkably precise and predictive, it cannot yet explain gravity, dark matter, or dark energy.

Explore all the particles that make up the Standard Model

This interactive organizes all the particles of matter and force in the Standard Model alongside the Higgs boson. Clicking on any particle will display a brief description and several properties, such as discovery year, mass, and charge.

The Higgs boson provides a mechanism that explains why some particles have mass

The mathematics of quantum field theory suggested that force particles should be massless, like the photon for electromagnetism, but the weak nuclear force’s equivalent W and Z particles are not. The Higgs field provides mass when interacting with such particles.

Antimatter is the oppositely charged version of normal matter

When a particle and its antiparticle collide, they annihilate each other, creating a burst of energy. This makes creating large amounts of antimatter challenging because it must be isolated from any surrounding normal matter or be destroyed.

Cosmic rays are high-energy particles from outside the solar system

Trillions of these particles moving close to the speed of light hit Earth daily, with some originating from beyond our galaxy. While the planet’s magnetic field blocks most, some collide with atoms in the atmosphere, producing cascades of exotic secondary particles.

A guide to building your own cloud chamber to observe cosmic rays

Using felt, alcohol, dry ice, and a clear container—such as a fish tank—you can create a region of supersaturated air that will cling to passing particles, forming trails of cloud-like droplets. Muons will create straight paths, alpha particles will leave thicker ones, and electrons or positrons will zigzag.

The trajectory of particles in bubble chambers reveals their properties

The presence of magnetic fields produces spiraling paths in charged particles as they move across the field, with faster and more massive particles moving in wider turns. Gaps in the trails indicate the presence of short-lived particles that are undetectable until they decay.

Virtual particles are bookkeeping tools used to describe force interactions

Physicists mathematically describe the electromagnetic, weak nuclear, and strong nuclear forces as the result of these particles being exchanged between particles of matter. Despite not being real, observable particles, this method has provided experimental predictions with an accuracy of over 12 decimal places.

Gravity, electromagnetism, and two nuclear forces make up nature’s fundamental forces

While gravity is the most familiar force, it is also the weakest and the only one without a particle to mediate the force. The weak nuclear force is responsible for radioactive decay and transmutation of elements, while the strong nuclear force holds quarks together.

View a breakdown of the mathematics behind the Standard Model

The Lagrangian version of the theory—related to the system's energy—presents a vast mathematical equation, with different components representing various force interactions and types of particles, including ghost particles to cancel out mathematical redundancies.