Particle physics

Particle physics, also called high-energy physics, is the study of the tiny pieces that make up everything in the universe. These tiny pieces are called fundamental particles. They combine to make the matter we see, like the atoms in our bodies and the stars in the sky.

The universe is made of two main types of particles described in the Standard Model. These are fermions, which are particles of matter, and bosons, which carry forces between particles. The matter we touch every day is made from the first group of fermions. This group includes particles called up and down quarks. These quarks come together to form protons and neutrons. Protons and neutrons are the pieces that make up the center, or nucleus, of an atom. Electrons, which orbit the nucleus, are also part of this group.

Quarks cannot exist alone. They combine to form particles called hadrons. The most familiar hadrons are protons and neutrons. These make up almost all the mass of everyday objects. Other hadrons, called mesons, are very short-lived. They are usually created when particles crash into each other at very high speeds, such as in cosmic rays or in special machines called particle accelerators. Every particle also has a matching antiparticle, like the positron. A positron is like an electron but with the opposite electric charge. These antiparticles could, in theory, form a kind of matter called antimatter.

Scientists study these particles using huge machines like the Large Hadron Collider. They also use theories and models to think about the role of particles in the universe. One of the most exciting discoveries was finding the Higgs boson. This particle was predicted by theory many years before it was found in experiments. Learning about particles helps us understand the very beginning of the universe and how everything came to be.

History

Main article: History of subatomic physics

The idea that everything is made of tiny building blocks called elementary particles goes back a long time. In the 1800s, a scientist named John Dalton discovered that each kind of material is made of one special type of particle, which we now call an atom. Later, scientists found that atoms are made of even smaller parts, like the electron.

In the early 1900s, scientists learned more about how atoms work. They found out that atoms could split apart, a process called nuclear fission, and that smaller particles could come together to form bigger ones, called nuclear fusion. These discoveries helped scientists learn more about the tiny particles that make up our world.

Standard Model

Main article: Standard Model

The Standard Model helps us understand the tiny pieces that make up everything around us. It explains how small particles called quarks and others work together through forces like the strong, weak, and electromagnetic forces. These particles can combine to form the matter we see and touch.

In 2012, scientists found a new particle called the Higgs boson. This particle was predicted by the Standard Model. While this model fits most of what we’ve observed, scientists think there might be more to discover about these tiny particles and the forces that guide them.

Subatomic particles

Particle physics studies tiny parts that make up everything around us, like electrons, protons, and neutrons. These tiny parts can also include things like photons, neutrinos, and muons, as well as many other unusual parts. All of these parts and how they work together are explained by something called the Standard Model.

These parts can act like tiny balls and like waves, depending on how we look at them. Some parts, called elementary particles, seem to be the simplest building blocks and cannot be broken down any further.

Main articles: Quark and Lepton

Ordinary matter is made from tiny building blocks called quarks and leptons. Quarks and leptons are known as fermions because they have a special kind of spin and follow certain rules. Quarks come in different types and have small electric charges, while leptons, like the electron, have whole-number charges.

Main article: Boson

There are also parts called bosons that carry forces between parts. For example, photons carry the force of electricity and magnetism, while other bosons carry forces that hold atoms together. The Higgs boson is special because it helps give mass to other parts.

Main articles: Antiparticle and Color charge

Every part has a matching antiparticle. When a part and its antiparticle meet, they can disappear and turn into other parts. Some parts, like photons, do not have antiparticles.

Main article: Composite particle

Larger parts, like protons and neutrons, are made from smaller parts called quarks. These larger parts are called hadrons. Scientists are also studying some unusual parts that might help us learn about the universe, like what makes up dark matter.

Main article: Composite particle

Experimental laboratories

Some of the biggest places where scientists study tiny particles are around the world. One is Brookhaven National Laboratory in New York, United States, where they crash heavy particles together. Another is CERN near Geneva, Switzerland, home to the Large Hadron Collider, which smashes particles at very high speeds.

Other important labs include DESY in Germany, Fermi National Accelerator Laboratory (Fermilab) in Illinois, United States, and KEK in Japan. These labs help scientists learn more about the tiny building blocks that make up everything around us.

Theory

Theoretical particle physics tries to create models and tools to help us understand experiments and predict future ones. Scientists work to better understand the Standard Model, which describes the tiny pieces that make up nature. They also explore ideas about what might exist beyond the Standard Model, like new types of symmetry or extra dimensions.

Another big area of study is string theory. In string theory, scientists try to combine two big ideas in physics—quantum mechanics and general relativity—by thinking of tiny strings instead of points. This could help create a complete theory that explains everything.

Practical applications

Learning about tiny particles helps us make useful inventions. Machines called particle accelerators help doctors treat sickness. They also make special materials that can carry electricity without losing power. Important technologies like the World Wide Web and touchscreen devices were created by scientists at a lab called CERN. These discoveries show how studying particles can help people in many ways.

Future

Scientists are working on new experiments to learn more about particles. Big projects like the Future Circular Collider at CERN and the Particle Physics Project Prioritization Panel in the US aim to discover new things. These efforts include plans for experiments such as the Deep Underground Neutrino Experiment to explore neutrinos, which are mysterious particles.