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In
physical sciences Physical science is a branch of natural science that studies abiotic component, non-living systems, in contrast to life science. It in turn has many branches, each referred to as a "physical science", together called the "physical sciences". ...

physical sciences
, a subatomic particle is a particle that is smaller than an
atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atom ...

atom
. According to the
Standard Model of particle physics The Standard Model of particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis ...

Standard Model of particle physics
, a subatomic particle can be either a
composite particle This is a list of known and hypothesized particles. Elementary particles Elementary particles are particles with no measurable internal structure; that is, it is unknown whether they are composed of other particles. They are the fundamental obj ...
, which is composed of other particles (for example, a
proton A proton is a subatomic particle, symbol or , with a positive electric charge of +1''e'' elementary charge and a mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collecti ...

proton
,
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...

neutron
, or
meson In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is th ...

meson
), or an
elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include the fundamental fermions (quarks, leptons, antiquarks, and an ...
, which is not composed of other particles (for example, an
electron The electron is a subatomic particle In physical sciences, subatomic particles are smaller than atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has ma ...

electron
,
photon The photon ( el, φῶς, phōs, light) is a type of elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be eleme ...

photon
, or
muon The muon (; from the Greek letter mu (μ) used to represent it) is an elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπι ...
).
Particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that ...
and
nuclear physics Nuclear physics is the field of physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related ent ...
study these particles and how they interact. Experiments show that light could behave like a stream of particles (called
photon The photon ( el, φῶς, phōs, light) is a type of elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be eleme ...

photon
s) as well as exhibiting wave-like properties. This led to the concept of
wave–particle duality Wave–particle duality is the concept in quantum mechanics that every particle or quantum entity may be described as either a particle or a wave. It expresses the inability of the classical physics, classical concepts "particle" or "wave" to ful ...
to reflect that quantum-scale behave like both particles and waves (they are sometimes described as waveicles to reflect this). Another concept, the
uncertainty principle In quantum mechanics Quantum mechanics is a fundamental Scientific theory, theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quant ...

uncertainty principle
, states that some of their properties taken together, such as their simultaneous position and
momentum In Newtonian mechanics, linear momentum, translational momentum, or simply momentum is the product of the mass Mass is both a property Property (''latin: Res Privata'') in the Abstract and concrete, abstract is what belongs to or w ...

momentum
, cannot be measured exactly. The wave–particle duality has been shown to apply not only to photons but to more massive particles as well. Interactions of particles in the framework of
quantum field theory In theoretical physics Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict List of natural phenomena, natural phenomena. This is in con ...
are understood as creation and annihilation of ''
quanta
quanta
'' of corresponding
fundamental interaction In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies matter, its Motion (physics), motion and behavior through Sp ...
s. This blends particle physics with field theory. Even among
particle physicists Particle physics (also known as high energy physics) is a branch of physics that studies the nature of the particles that constitute matter and radiation. Although the word ''particle'' can refer to various types of very small objects (e.g. prot ...
, the exact definition of a particle has diverse descriptions. These professional attempts at the definition of a particle include: * A particle is a collapsed wave function * A particle is a quantum excitation of a field * A particle is an irreducible representation of the Poincaré group * A particle might be a
vibrating strings in a string. The fundamental and the first 5 overtones in the harmonic series. A vibration in a string is a wave. Resonance causes a vibrating string to produce a sound In physics Physics (from grc, φυσική (ἐπιστή ...

vibrating string
* A particle is a
thing measured in a detector
thing measured in a detector


Classification


By composition

Subatomic particles are either "elementary", i.e. not made of multiple other particles, or "composite" and made of more than one elementary particle bound together. The elementary particles of the
Standard Model The Standard Model of particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis ...

Standard Model
are: * Six "
flavors Flavor, or flavour, is the perceptual Perception (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area arou ...
" of
quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge ...

quark
s:
up
up
,
down Down most often refers to: * Down, the relative direction opposed to up * Down (gridiron football), in American/Canadian football, a period when one play takes place * Down feather, a soft bird feather used in bedding and clothing * Downland, a typ ...

down
,
strange
strange
,
charm Charm may refer to: Social science * Charisma, a person or thing's pronounced ability to attract others * Superficial charm, the tendency to be smooth, engaging, charming, slick and verbally facile Science and technology * Charm quark, a type of e ...

charm
,
bottom
bottom
, and
top A spinning top, or simply a top, is a toy with a squat body and a sharp point at the bottom, designed to be spun on its vertical axis, balancing on the tip due to the gyroscopic effect. Once set in motion, a top will usually wobble for a few ...

top
; * Six types of
lepton In particle physics, a lepton is an elementary particle of half-integer spin (spin (physics), spin ) that does not undergo strong interactions. Two main classes of leptons exist: electric charge, charged leptons (also known as the electron-like ...

lepton
s:
electron The electron is a subatomic particle In physical sciences, subatomic particles are smaller than atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has ma ...

electron
,
electron neutrino The electron neutrino () is a subatomic lepton In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowle ...

electron neutrino
,
muon The muon (; from the Greek letter mu (μ) used to represent it) is an elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπι ...
,
muon neutrino The muon neutrino is a lepton, an elementary subatomic particle which has the symbol and no electric charge Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. Ther ...

muon neutrino
,
tau Tau (uppercase Τ, lowercase τ; el, ταυ ) is the 19th letter of the Greek alphabet The Greek alphabet has been used to write the Greek language since the late ninth or early eighth century BC. It is derived from the earlier Phoenician ...
,
tau neutrino The tau neutrino or tauon neutrino is a subatomic elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ ( ...

tau neutrino
; * Twelve
gauge boson 300px, The Standard Model of elementary particles, with the gauge bosons in the fourth column in red In particle physics, a gauge boson is a bosonic elementary particle that mediates interactions among elementary fermions, and thus acts as a force ...
s (force carriers): the
photon The photon ( el, φῶς, phōs, light) is a type of elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be eleme ...

photon
of
electromagnetism Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electric charge, electrically charged particles. The electromagnetic force is carried by electromagnet ...

electromagnetism
, the three
W and Z bosons In particle physics, the W and Z bosons are vector bosons that are together known as the weak bosons or more generally as the intermediate vector bosons. These elementary particles force carrier, mediate the weak interaction; the respective symbol ...
of the
weak force Weak may refer to: Songs * "Weak" (AJR song), 2016 * "Weak" (Melanie C song), 2011 * Weak (SWV song), "Weak" (SWV song), 1993 * Weak (Skunk Anansie song), "Weak" (Skunk Anansie song), 1995 * "Weak", a song by Seether from ''Seether: 2002-2013'' ...
, and the eight
gluon A gluon () is an elementary particle that acts as the exchange particle (or gauge boson) for the strong force between quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy ...

gluon
s of the
strong force In nuclear physics and particle physics, the strong interaction is the mechanism responsible for the strong nuclear force, and is one of the four known fundamental interactions, with the others being electromagnetism, the weak interaction, and ...
; * The
Higgs boson The Higgs boson is an elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include the fundamen ...

Higgs boson
. All of these have now been discovered by experiments, with the latest being the top quark (1995), tau neutrino (2000), and Higgs boson (2012). Various extensions of the Standard Model predict the existence of an elementary
graviton In theories of quantum gravity, the graviton is the hypothetical quantum of gravity Gravity (), or gravitation, is a list of natural phenomena, natural phenomenon by which all things with mass or energy—including planets, stars, galaxy ...
particle and many other elementary particles, but none have been discovered as of 2021.


Hadrons

Nearly all composite particles contain multiple quarks (and/or antiquarks) bound together by gluons (with a few exceptions with no quarks, such as
positronium Positronium (Ps) is a system consisting of an electron and its anti-particle, a positron The positron or antielectron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge Electric charg ...

positronium
and
muonium Muonium is an exotic atom made up of an antimuon and an electron The electron is a subatomic particle, symbol or , whose electric charge Electric charge is the physical property of matter that causes it to experience a force when placed ...

muonium
). Those containing few (≤ 5) ntiuarks are called
hadron In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the ...
s. Due to a property known as
color confinement Color (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American English ...
, quarks are never found singly but always occur in hadrons containing multiple quarks. The hadrons are divided by number of quarks (including antiquarks) into the
baryons In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is th ...
containing an odd number of quarks (almost always 3), of which the
proton A proton is a subatomic particle, symbol or , with a positive electric charge of +1''e'' elementary charge and a mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collecti ...

proton
and
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...

neutron
(the two
nucleons In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they under ...
) are by far the best known; and the
meson In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is th ...

meson
s containing an even number of quarks (almost always 2, one quark and one antiquark), of which the
pion In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is th ...

pion
s and
kaon In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the ...

kaon
s are the best known. Except for the proton and neutron, all other hadrons are unstable and decay into other particles in microseconds or less. A proton is made of two
up quark The up quark or u quark (symbol: u) is the lightest of all quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, ...

up quark
s and one
down quark The down quark or d quark (symbol: d) is the second-lightest of all quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (fro ...

down quark
, while the neutron is made of two down quarks and one up quark. These commonly bind together into an atomic nucleus, e.g. a
helium-4 Helium-4 () is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on Earth. Its nucleus is identical to an alpha particle, and consists ...

helium-4
nucleus is composed of two protons and two neutrons. Most hadrons do not live long enough to bind into nucleus-like composites; those who do (other than the proton and neutron) form exotic nuclei.


By statistics

Any subatomic particle, like any particle in the
three-dimensional space Three-dimensional space (also: 3-space or, rarely, tri-dimensional space) is a geometric setting in which three values (called parameters) are required to determine the position of an element (i.e., point). This is the informal meaning of the ...
that obeys the
laws Law is a system of rules created and law enforcement, enforced through social or governmental institutions to regulate behavior,Robertson, ''Crimes against humanity'', 90. with its precise definition a matter of longstanding debate. It has be ...
of
quantum mechanics Quantum mechanics is a fundamental Scientific theory, theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quan ...
, can be either a
boson In quantum mechanics, a boson (, ) is a particle that follows Bose–Einstein statistics. Bosons make up one of two classes of elementary particles, the other being fermions. The name boson was coined by Paul Dirac to commemorate the contributio ...

boson
(with integer
spin Spin or spinning may refer to: Businesses * SPIN (cable system) or South Pacific Island Network * Spin (company), an American scooter-sharing system * SPiN, a chain of table tennis lounges Computing * SPIN model checker, Gerard Holzmann's tool fo ...
) or a
fermion In particle physics, a fermion is a particle that follows Fermi–Dirac statistics and generally has half odd integer spin: spin 1/2, Spin (physics)#Higher spins, spin 3/2, etc. These particles obey the Pauli exclusion principle. Fermions include ...
(with odd half-integer spin). In the Standard Model, all the elementary fermions have spin 1/2, and are divided into the
quarks A quark () is a type of elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include the fundamen ...

quarks
which carry
color charge Color charge is a property of quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη ...
and therefore feel the strong interaction, and the
leptons In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is ...
which do not. The elementary bosons comprise the
gauge bosons 300px, The Standard Model of elementary particles, with the gauge bosons in the fourth column in red In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐ ...
(photon, W and Z, gluons) with spin 1, while the
Higgs boson The Higgs boson is an elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. Particles currently thought to be elementary include the fundamen ...

Higgs boson
is the only elementary particle with spin zero. The hypothetical
graviton In theories of quantum gravity, the graviton is the hypothetical quantum of gravity Gravity (), or gravitation, is a list of natural phenomena, natural phenomenon by which all things with mass or energy—including planets, stars, galaxy ...
is required theoretically to have spin 2, but is not part of the Standard Model. Some extensions such as
supersymmetry In a supersymmetric theory the equations for force and the equations for matter are identical. In theoretical physics, theoretical and mathematical physics, any theory with this property has the principle of supersymmetry (SUSY). Dozens of super ...
predict additional elementary particles with spin 3/2, but none have been discovered as of 2021. Due to the laws for spin of composite particles, the baryons (3 quarks) have spin either 1/2 or 3/2, and are therefore fermions; the mesons (2 quarks) have integer spin of either 0 or 1, and are therefore bosons.


By mass

In
special relativity In physics, the special theory of relativity, or special relativity for short, is a scientific theory regarding the relationship between Spacetime, space and time. In Albert Einstein's original treatment, the theory is based on two Postulates of ...
, the energy of a particle at rest equals its mass times the speed of light squared, ''E'' = ''mc''2. That is,
mass Mass is the physical quantity, quantity of ''matter'' in a physical body. It is also a measure (mathematics), measure of the body's ''inertia'', the resistance to acceleration (change of velocity) when a net force is applied. An object's mass ...
can be expressed in terms of
energy In physics, energy is the physical quantity, quantitative physical property, property that must be #Energy transfer, transferred to a physical body, body or physical system to perform Work (thermodynamics), work on the body, or to heat it. En ...

energy
and vice versa. If a particle has a
frame of reference In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force. ...

frame of reference
in which it lies at rest, then it has a positive
rest mass The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** ...
and is referred to as ''massive''. All composite particles are massive. Baryons (meaning "heavy") tend to have greater mass than mesons (meaning "intermediate"), which in turn tend to be heavier than leptons (meaning "lightweight"), but the heaviest lepton (the tau particle) is heavier than the two lightest flavours of baryons (nucleons). It is also certain that any particle with an electric charge is massive. When originally defined in the 1950s, the terms baryons, mesons and leptons referred to masses; however, after the quark model became accepted in the 1970s, it was recognised that baryons are composites of three quarks, mesons are composites of one quark and one antiquark, while leptons are elementary and are defined as the elementary fermions with no
color charge Color charge is a property of quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη ...
. All massless particles (particles whose invariant mass is zero) are elementary. These include the photon and gluon, although the latter cannot be isolated.


By decay

Most subatomic particles are not stable. All leptons, as well as baryons particle decay, decay by either the strong force or weak force (except for the proton). Protons are not known to Proton decay, decay, although whether they are "truly" stable is unknown, as some very important Grand Unified Theories (GUTs) actually require it. The μ and τ muons, as well as their antiparticles, decay by the weak force. Neutrinos (and antineutrinos) do not decay, but a related phenomenon of neutrino oscillations is thought to exist even in vacuums. The electron and its antiparticle, the positron, are theoretically stable due to charge conservation unless a lighter particle having absolute value, magnitude of electric charge  elementary charge, ''e'' exists (which is unlikely). Its charge is not shown yet


Other properties

All observable subatomic particles have their electric charge an integer multiple of the elementary charge. The Standard Model's
quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge ...

quark
s have "non-integer" electric charges, namely, multiple of  ''e'', but quarks (and other combinations with non-integer electric charge) cannot be isolated due to
color confinement Color (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American English ...
. For baryons, mesons, and their antiparticles the constituent quarks' charges sum up to an integer multiple of ''e''. Through the work of Albert Einstein, Satyendra Nath Bose, Louis de Broglie, and many others, current scientific theory holds that ''all'' particles also have a wave nature. This has been verified not only for elementary particles but also for compound particles like atoms and even molecules. In fact, according to traditional formulations of non-relativistic quantum mechanics, wave–particle duality applies to all objects, even macroscopic ones; although the wave properties of macroscopic objects cannot be detected due to their small wavelengths. Interactions between particles have been scrutinized for many centuries, and a few simple laws underpin how particles behave in collisions and interactions. The most fundamental of these are the laws of conservation of energy and conservation of momentum, which let us make calculations of particle interactions on scales of magnitude that range from stars to
quark A quark () is a type of elementary particle In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge ...

quark
s. These are the prerequisite basics of Newtonian mechanics, a series of statements and equations in ''Philosophiae Naturalis Principia Mathematica'', originally published in 1687.


Dividing an atom

The negatively charged electron has a mass equal to of that of a hydrogen atom. The remainder of the hydrogen atom's mass comes from the positively charged
proton A proton is a subatomic particle, symbol or , with a positive electric charge of +1''e'' elementary charge and a mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collecti ...

proton
. The atomic number of an element is the number of protons in its nucleus. Neutrons are neutral particles having a mass slightly greater than that of the proton. Different isotopes of the same element contain the same number of protons but differing numbers of neutrons. The mass number of an isotope is the total number of nucleons (neutrons and protons collectively). Chemistry concerns itself with how electron sharing binds atoms into structures such as crystals and molecules. The subatomic particles considered important in the understanding of chemistry are the
electron The electron is a subatomic particle In physical sciences, subatomic particles are smaller than atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has ma ...

electron
, the
proton A proton is a subatomic particle, symbol or , with a positive electric charge of +1''e'' elementary charge and a mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collecti ...

proton
, and the
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...

neutron
. Nuclear physics deals with how protons and neutrons arrange themselves in nuclei. The study of subatomic particles, atoms and molecules, and their structure and interactions, requires
quantum mechanics Quantum mechanics is a fundamental Scientific theory, theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quan ...
. Analyzing processes that change the numbers and types of particles requires
quantum field theory In theoretical physics Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict List of natural phenomena, natural phenomena. This is in con ...
. The study of subatomic particles ''per se'' is called particle physics. The term ''high-energy physics'' is nearly synonymous to "particle physics" since creation of particles requires high energies: it occurs only as a result of cosmic rays, or in particle accelerators. phenomenology (particle physics), Particle phenomenology systematizes the knowledge about subatomic particles obtained from these experiments.Taiebyzadeh, Payam (2017). String Theory; A unified theory and inner dimension of elementary particles (BazDahm). Riverside, Iran: Shamloo Publications Center. .


History

The term "''subatomic'' particle" is largely a retronym of the 1960s, used to distinguish a large number of baryons and
meson In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is th ...

meson
s (which comprise
hadron In particle physics Particle physics (also known as high energy physics) is a branch of physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the ...
s) from particles that are now thought to be elementary particle, truly elementary. Before that hadrons were usually classified as "elementary" because their composition was unknown. A list of important discoveries follows:


See also


References


Further reading

;General readers * Richard Feynman, Feynman, R.P. & Steven Weinberg, Weinberg, S. (1987). ''Elementary Particles and the Laws of Physics: The 1986 Dirac Memorial Lectures''. Cambridge Univ. Press. * * Oerter, Robert (2006). ''The Theory of Almost Everything: The Standard Model, the Unsung Triumph of Modern Physics''. Plume. * Schumm, Bruce A. (2004). ''Deep Down Things: The Breathtaking Beauty of Particle Physics''. Johns Hopkins University Press. . * ;Textbooks * Coughlan, G.D., J.E. Dodd, and B.M. Gripaios (2006). ''The Ideas of Particle Physics: An Introduction for Scientists'', 3rd ed. Cambridge Univ. Press. An undergraduate text for those not majoring in physics. * *


External links


particleadventure.org: The Standard Model.University of California: Particle Data Group.Jose Galvez: Chapter 1 Electrodynamics (pdf).
{{DEFAULTSORT:Subatomic Particle Subatomic particles, Quantum mechanics