QCE Physics Unit 4 Topic 3 - The Standard Model Definitions

Antiparticle

A subatomic particle of the same mass but different charge and spin to a corresponding particle.

Elementary Particle

A particle whose substructure is unknown.

Gauge Bosons

Carrier or exchange particles that govern particle interaction and the mediation of the four fundamental forces.

Electromagnetic Force

One of the four fundamental forces; Mediated by photons

Weak Nuclear Force

One of the four fundamental forces; Mediated by W and Z bosons and is responsible for radioactive decays.

Strong Nuclear Force

One of the four fundamental forces; Acts over small distances to hold nucleons together from repulsive electrostatic force. Mediated by gluons.

Quarks

Subatomic particles governed by strong nuclear force that constitute hadrons.

Leptons

Particles governed by the weak nuclear force and influenced by electromagnetism due to their charge.

Lepton Number

A conserved quantum number defined by L = nl - nlbar.

Baryons

Composite subatomic particles made up of three quarks.

Baryon Number

A strictly conserved additive quantum number of a system defined as B = 1/3(nq - nqbar)

Mesons

Subatomic particles composed of one quark and one antiquark.