Particle Physics

Basics

The three types of 'composite particle' that make up an atom are:

Particle that orbits the nucleus: negative charge, but negligible mass compared to the nuclear particles (approximately 1/1836 as much); discovered and identified in 1897 by Manchester–born physicist J. J. Thomson		Electron
Nuclear particle with positive charge and mass of approximately one atomic mass unit; discovered and named in 1917 by New Zealander Joseph Rutherford (working in Cambridge)		Proton
The atomic number of an element is determined by the number of these in the nuclei of its atoms
Nuclear particle with zero charge and mass of approximately one atomic mass unit; discovered in 1932 by James Chadwick (born in Bollington, Cheshire)		Neutron

Radioactive Particles

An alpha particle is effectively the nucleus of an atom of		Helium
A beta particle consists of		An electron or a positron
A gamma ray consists of		Electromagnetic radiation (photons)

Other

The three types of elementary particle (in the Standard Model of particle physics)		Quark
		Lepton
		Boson

The six 'flavours' of quark:

Up

Down

Strange

Charm

Top

Bottom

The six 'flavours' of lepton:

	Electron		Muon		Tau
	Electron neutrino		Muon neutrino		Tau neutrino

A first–generation (i.e. the most familiar type of) lepton, with a charge		Electron
A lepton with negligible mass and zero charge (three generations); emitted by the sun, passes straight through the Earth; it's said that approximately 1020 (one hundred quintillion – a quintillion being a million million million) pass through every person's body every second		Neutrino
Common name for quarks and leptons – the basic building blocks of matter (named after an Italian nuclear physicist, 1901–54)		Fermion
Elementary particles that (in layman's terms) are associated with forces rather than matter		Bosons
Generic term for all particles made up of quarks		Hadron
Composite particle (hadron) made up of three quarks; the proton and neutron are the two most stable types of		Baryon
The other type of hadron (other than baryons) – made up of one quark and one antiquark		Meson
Baryon (hadron) comprising one up quark and two down quarks		Neutron
Baryon (hadron) comprising two up quarks and one down quark		Proton
Collective name for protons and neutrons		Nucleon
The last Standard Model particle to be observed – its existence was confirmed in 2016; named after a professor at Edinburgh University who was one of the first to hypothesise it (1964); nicknamed 'the God particle'		Higgs boson
The basic 'unit' of light, and of all forms of electromagnetic radiation; the force carrier of the electromagnetic force. Concept developed by Einstein to explain observations that didn't fit the wave model of light		Photon
The anti–particle of the electron (same mass, positive charge) – a.k.a. anti–electron		Positron
Particle that mediates the weak force and has a charge (positive or negative)		W boson
Particle that mediates the weak force and has zero charge		Z boson
Hold the protons and neutrons together in an atomic nucleus		Gluons
Photons, W and Z bosons, and gluons, collectively		Gauge bosons

© Haydn Thompson 2017–22