Particles Key Terms

interaction diagram

A visual representation that illustrates the interactions between particles, showing the exchange particles involved.

exchange particle

A particle that mediates interactions between other particles, such as photons for electromagnetic forces or W bosons for weak interactions.

Hadrons

Hadrons are composite particles made up of quarks, which are held together by the strong force. They include baryons (such as protons and neutrons) and mesons.

Leptons

Leptons are fundamental particles that do not undergo strong interactions. They include electrons, muons, and neutrinos.

Baryon

A type of subatomic particle made up of three quarks, which includes protons and neutrons.

Meson

A type of subatomic particle composed of one quark and one antiquark, which mediates strong interactions.

lepton

A fundamental particle that does not undergo strong interactions, such as electrons, muons, and neutrinos.

neutrino

A neutral subatomic particle with a very small mass, produced in nuclear reactions, and interacts only via the weak force.

lepton number

A quantum number that represents the total number of leptons in a particle interaction, which must be conserved.

baryon number

A quantum number that represents the total number of baryons in a particle interaction, which must be conserved.

Charge of Up Quark

The up quark has a charge of +2/3e, where e is the elementary charge.

Charge of Down Quark

The down quark has a charge of -1/3e, where e is the elementary charge.

quark composition

The specific arrangement of quarks that make up baryons and mesons, determining their properties.

baryon

A type of hadron composed of three quarks, which includes protons and neutrons.

Beta decay

A type of radioactive decay in which a beta particle (electron or positron) is emitted from an atomic nucleus.

Quark change

The process by which one type of quark is transformed into another type, often observed in beta decay.

Charge Conservation

The principle that the total electric charge in an isolated system remains constant over time.

Strangeness Conservation

The principle that the total strangeness quantum number is conserved in particle interactions.

conservation law

A principle stating that certain properties of isolated systems remain constant over time, such as charge, baryon number, and lepton number.

particle interaction

A process in which particles influence each other through fundamental forces, often mediated by exchange particles.

Charge Conservation

The principle that the total electric charge in an isolated system remains constant over time.

Baryon Number Conservation

The principle that the total baryon number in a closed system remains unchanged during a particle interaction.

conservation laws

Principles that dictate that certain properties, such as charge, baryon number, and lepton number, remain constant in particle interactions.

proposed particle interactions

Hypothetical interactions between particles that may violate conservation laws, leading to the conclusion that they cannot occur.

conservation of charge

The principle stating that the total electric charge in an isolated system remains constant over time.

decay equation

A mathematical representation of the transformation of one or more particles into different particles during radioactive decay.