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Classification of Particles

Classification of Particles

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Particle classification is an important aspect of understanding the universe. Scientists have discovered many particles over the years, including electrons, protons, neutrinos, and neutrons. These particles are considered the building blocks of the universe and are part of a larger family of particles. Knowing how these particles are classified is crucial to understanding the world around us.

How many particles are there?

At the moment, the standard model features seventeen elemental particles. It includes particles like quarks, which make up matter, and photons, which are responsible for the energy exchanges in the matter.

Installation of the Large Hadron Collider, which is used for research on elementary particles
Installation of the Large Hadron Collider, which is used for research on elementary particles

What is the classification of elemental particles?

When it comes to understanding elemental particles, classification is key. Scientists have classified particles based on their properties and interactions, with three large families emerging as the particle count increased. These families are leptons, hadrons, and field carriers (bosons). Each family has its own unique characteristics and is subject to different forces, making them play different roles in the universe. So, understanding particle classification is crucial for understanding the workings of the universe.

Particle classification chart

The particles can be classified as follows:

Classification of elemental particles with examples of the members of each family, some of which overlap
Classification of elemental particles with examples of the members of each family, some of which overlap

Quarks

Hadrons, the particles that make up atoms, are made up of even smaller particles called quarks. Quarks are responsible for giving hadrons their charge. Protons and neutrons, for example, are made up of the bottom quark and the down quark. Each quark has its own unique charge. Quarks, as well as electrons and neutrinos, belong to another sub-family called fermions. By understanding the properties of quarks, we can better understand the behavior of matter in the universe.

Quarks and hadrons

The charge of a particle is determined by the sum of the charges of the quarks that make it up. For example, a proton is made up of two up quarks and one down quark, so its charge is1. An antiproton is made up of two anti-up quarks and one anti-down quark, so its charge is -1.

The baryon number of a particle is determined by the number of quarks minus the number of antiquarks divided by 3. For example, a proton has a baryon number of +1, while an antiproton has a baryon number of -1.

The strange number of a particle is determined by the number of strange quarks minus the number of anti-strange quarks. Strange particles are formed when high-energy beams collide with atoms and they disintegrate more slowly than other quarks.

By adding the charge and baryon number of a particle, we can determine if it is matter or antimatter. For example, a proton has a charge of +1 and a baryon number of +1, so it is matter. An antiproton has a charge of -1 and a baryon number of -1, so it is antimatter.

Hadrons

Hadrons are fundamental particles that make up the majority of the mass in the universe. The strong nuclear force is what holds hadrons together, binding all particles that make up the nucleus. Hadrons are made up of quarks, and quarks carry the electric charge of the hadrons.

The proton is an example of a hadron that consists of three quarks, two of which have a charge of ⅔ e, while the third has a charge of -⅓ e. The total charge of a proton is +1 e.

Hadrons can be classified into two categories: mesons and baryons. Mesons consist of an even number of quarks, while baryons consist of an odd number of quarks.

Antiquarks and antimatter are counterparts to quarks, electrons, protons, and neutrons. They belong to the same family, but some of their characteristics, such as the electrical charge, are opposite. Antimatter particles include positrons, antiprotons, and antineutrons. Understanding the properties of hadrons and their components can help us better understand the in the universe.

Leptons

Leptons are elemental particles that cannot split themselves into smaller particles. They are not affected by the strong nuclear force that keeps protons and neutrons together in the nucleus. Leptons have a charge like hadrons, they are affected by the weak nuclear force, and they can be classified into charged particles and neutral particles.

Charged: they possess and carry electrical charges like the electron, muon, and tau. Neutral: their charge is zero like that of neutrons.

Field particles or force carriers

The universe is made up of particles that comprise matter and four elemental forces or bosons that govern how these particles interact with each other. These four forces are gravity, the electromagnetic force, the strong nuclear force, and the weak nuclear force.

Gravity is the force that governs the motion of celestial bodies and is responsible for keeping planets in orbit around stars. The particle that mediates this force is known as the graviton, although it has not yet been detected.

The electromagnetic force is responsible for the interaction between charged particles and the movement of electrically charged particles. The particle responsible for carrying this force is the photon, which interacts with atoms and transfers energy between them.

The strong nuclear force is responsible for binding together the protons and neutrons in the nucleus of an atom. It is the strongest of the four fundamental forces and is mediated by the gluon.

The weak nuclear force is responsible for nuclear decay and is involved in the creation of energy in stars. The particle that mediates this force is the W and Z bosons.

Understanding these fundamental forces is crucial for understanding the behavior of matter and energy in the universe. The search for the graviton and the study of these bosons and their interactions with matter continues to be an area of active research in physics.

The Higgs boson

The discovery of the Higgs boson, proposed by Peter Higgs, was a significant breakthrough in particle physics, as it provided insight into how particles acquire mass. The Higgs boson was discovered in the Large Hadron Collider (LHC).

There are currently seventeen elementary particles that make up matter and energy interactions in the universe. These particles can be divided into three categories: hadrons, leptons, and force carriers or field particles. Force carriers are responsible for transmitting energy between other particles. The graviton, an example of a force carrier, has yet to be discovered.

Hadrons are composed of further elemental particles called quarks, which give them their charge. Leptons, on the other hand, do not contain quarks. The charge of matter is defined by the quark charge and baryon number.

Understanding the classification of particles is essential in understanding the behavior of matter and energy in the universe. The discovery of the Higgs boson and the search for other fundamental particles continue to be an area of active research in particle physics.

Classification of Particles

How do you classify particles?

Particles are classified into hadrons, leptons and force field carriers.

What are quarks?

Quarks are particles that make up other particles.

Are hadrons made up of quarks?

Yes, they are.

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