TXT

{{Author|Harold Foppele}}
{{Physics}}
{{Quiz}}
{{Learning project}}
←[[Quantum]]
[[File:Artistic impression of an atom 5.png|thumb|Artistic impression of an atom 5]]
This page offers a guide to the different types of matter in the universe. From chemical elements to fundamental [[W:Particl|particles]].  It gives an overview of [[W:Atom|atoms]], [[W:Subatomic particle|subatomic particles]], and [[W:Composite particles|composite particles]].  The building blocks of matter and how they combine to form everything.  It shows [[Chemical element|chemical elements]] and its arrangement in the periodic table.<ref name="IUPAC"/>  Describes the [[W:Standard Model of physics|Standard Model]], and list the fundamental particles and the forces they have.<ref name="CERN"/>  Composite particles like [[W:proton|protons]], [[W:neutron|neutrons]], and [[W:meson|mesons]] show how [[W:quark|quarks]] form larger structures.<ref name="PDG"/> Visual aids, tables, and formulas help illustrate particle types and their relationships. This resource is intended for students, educators, and anyone curious about the structure of matter.
===How many different Elements and Particles Exist?===
[[File:Hydrogen discharge tube.jpg|thumb|[[W:Hydrogen|Hydrogen]] in its [[W:plasma (physics)|plasma]] state is the most abundant ordinary matter in the universe.]]
The universe is made of tiny building blocks, known as particles. These particles combine to form atoms, molecules, and matter. Elements contain only one type of atom. There are 118 known chemical elements, each with properties and atomic structure.<ref name="IUPAC"/>  Atoms are made of subatomic particles: protons, neutrons, and [[W:electron|electrons]].<ref name="Fermilab"/>  Protons and neutrons are made of quarks, which are matter particles.<ref name="PDG"/>  The Standard Model of physics includes all known fundamental particles and the forces between them.<ref name="CERN"/>  Composite particles, such as [[W:hadron|hadrons]] and mesons, are formed from combinations of quarks.<ref name="PDG"/>  By studying these particles scientists find the structure, behavior, and evolution of the universe.

The following diagram illustrates the tri-partite metaphysical scheme for analyzing parts of material nature.
[[File:Tri-partite meta scheme.svg|tri-partite metaphysical scheme]|center|800px]]
This diagram also illustrates the power of visualization to communicate information between human minds, especially about objects
and relationships. There is limited use of language (only verbal ‘tags’), no mathematics while the figures could be any shape or color.
== 1. Overview ==
{| class="wikitable"
! Level !! Count !! Description
|-
| Chemical elements || 118 || Periodic table atoms<ref name="IUPAC"/>
|-
| Fundamental particles || 31–32 || Standard Model building blocks<ref name="CERN"/>
|-
| Common subatomic particles || Dozens || Electrons, protons, neutrons, etc.<ref name="Fermilab"/>
|-
| Composite particles || 400+ || Hadrons, mesons, exotic states<ref name="PDG"/>
|}

== 2. Chemical Elements (Periodic Table) ==
There are 118 confirmed elements.<ref name="IUPAC"/>

{{Template:Periodic table (navbox)}}

==Gallery==
Alternative periodic table expressions
<gallery>
File:ADOMAH periodic table - electron orbitals (polyatomic).svg|ADOMAH (long)
File:The chemical elements and their periodic relationships.svg|Curled ribbon (continuous)
File:Mendeleev flower.jpg|Four loops (continuous)
File:Partially disordered PT.png|Partially disordered (unclassified)
File:Hackh's PT (1918).png|{{anchor|Hackh}}Short (9/11 columns)<!--This table is linked from a footnote to the article-->
File:Notes to Hackh's PT (1918).png|Short (9/11 columns) notes
File:Periodic table (spiral format).SVG|Spiral
File:Periodic ziggurat part 1.png|Ziggurat (unclassified)
File:Periodic ziggurat part 2.png|Ziggurat notes
File:4DPeriodicTable.png|4D Stowe-Scerri (spatial)
</gallery>
== 2.1 All known elements==

{{Quantum mechanics}}

<div style="column-count:3; font-size=45%;">
[[Hydrogen]], [[Helium]], [[Lithium]], [[W:Beryllium|Beryllium]], [[Boron]], [[W:Carbon|Carbon]], [[W:Nitrogen|Nitrogen]], [[W:Oxygen|Oxygen]], [[W:Fluorine|Fluorine]], [[W:Neon|Neon]], [[W:Sodium|Sodium]], [[W:Magnesium|Magnesium]], [[W:Aluminum|Aluminum]], [[W:Silicon|Silicon]], [[W:Phosphorus|Phosphorus]], [[W:Sulfur|Sulfur]], [[W:Chlorine|Chlorine]], [[W:Argon|Argon]], [[W:Potassium|Potassium]], [[W:Calcium|Calcium]], [[W:Scandium|Scandium]], [[W:Titanium|Titanium]], [[W:Vanadium|Vanadium]], [[W:Chromium|Chromium]], [[W:Manganese|Manganese]], [[W:Iron|Iron]], [[W:Cobalt|Cobalt]], [[W:Nickel|Nickel]], [[W:Copper|Copper]], [[W:Zinc|Zinc]], [[W:Gallium|Gallium]], [[W:Germanium|Germanium]], [[W:Arsenic|Arsenic]], [[W:Selenium|Selenium]], [[W:Bromine|Bromine]], [[W:Krypton|Krypton]], [[W:Rubidium|Rubidium]], [[W:Strontium|Strontium]], [[W:Yttrium|Yttrium]], [[W:Zirconium|Zirconium]], [[W:Niobium|Niobium]], [[W:Molybdenum|Molybdenum]], [[W:Technetium|Technetium]], [[W:Ruthenium|Ruthenium]], [[W:Rhodium|Rhodium]], [[W:Palladium|Palladium]], [[W:Silver|Silver]], [[W:Cadmium|Cadmium]], [[W:Indium|Indium]], [[W:Tin|Tin]], [[W:Antimony|Antimony]], [[W:Tellurium|Tellurium]], [[W:Iodine|Iodine]], [[W:Xenon|Xenon]], [[W:Cesium|Cesium]], [[W:Barium|Barium]], [[W:Lanthanides|Lanthanides]], [[W:Hafnium|Hafnium]], [[W:Tantalum|Tantalum]], [[W:Tungsten|Tungsten]], [[W:Rhenium|Rhenium]], [[W:Osmium|Osmium]], [[W:Iridium|Iridium]], [[W:Platinum|Platinum]], [[W:Gold|Gold]], [[W:Mercury|Mercury]], [[W:Thallium|Thallium]], [[W:Lead|Lead]], [[W:Bismuth|Bismuth]], [[W:Polonium|Polonium]], [[W:Astatine|Astatine]], [[W:Radon|Radon]], [[W:Francium|Francium]], [[W:Radium|Radium]], [[W:Actinides|Actinides]], [[W:Rutherfordium|Rutherfordium]], [[W:Dubnium|Dubnium]], [[W:Seaborgium|Seaborgium]], [[W:Bohrium|Bohrium]], [[W:Hassium|Hassium]], [[W:Meitnerium|Meitnerium]], [[W:Darmstadtium|Darmstadtium]], [[W:Roentgenium|Roentgenium]], [[W:Copernicium|Copernicium]], [[W:Nihonium|Nihonium]], [[W:Flerovium|Flerovium]], [[W:Moscovium|Moscovium]], [[W:Livermorium|Livermorium]], [[W:Tennessine|Tennessine]], [[W:Oganesson|Oganesson]]<ref name="IUPAC"/>
</div>

== 3. Subatomic Particles ==
<div style="float:right; margin: 0 0 1em 1em;">
{| class="wikitable"
|+ Common subatomic particles
|-
! Particle !! Type !! Notes
|-
| Electron || Lepton || Fundamental<ref>Fermilab. "Electron." Fermilab Particle Data. https://www.fnal.gov/</ref>
|-
| Proton || Baryon || Composed of quarks<ref>Particle Data Group (PDG). "Proton." *Review of Particle Physics*, 2022. https://pdg.lbl.gov/</ref>
|-
| Neutron || Baryon || Composed of quarks<ref>Particle Data Group (PDG). "Neutron." *Review of Particle Physics*, 2022. https://pdg.lbl.gov/</ref>
|-
| Photon || Boson || Force carrier (electromagnetism)<ref>CERN. "Photon." CERN Document Server. https://home.cern/science/physics/photon</ref>
|-
| Neutrinos || Lepton || Three flavors<ref>Particle Data Group (PDG). "Neutrinos." *Review of Particle Physics*, 2022. https://pdg.lbl.gov/</ref>
|-
| Muon || Lepton || Heavier electron<ref>Fermilab. "Muon." Fermilab Particle Data. https://www.fnal.gov/</ref>
|-
| Tau || Lepton || Heaviest lepton<ref>Fermilab. "Tau." Fermilab Particle Data. https://www.fnal.gov/</ref>
|-
| Quarks || Fermion || Six flavours (u, d, s, c, t, b)<ref>Particle Data Group (PDG). "Quarks." *Review of Particle Physics*, 2022. https://pdg.lbl.gov/</ref>
|}
</div>
<br><br>
In 1985, Alan Chodos <ref>Chodos, Alan. "Reference Paper." *SCIRP References*. Accessed 27 November 2025. https://www.scirp.org/reference/referencespapers?referenceid=3609068</ref>
proposed that [[W:neutrino|neutrino]]s can have a tachyonic nature.<ref>Chodos, A. (1985). "The neutrino as a tachyon." *Physics Letters B*, 150(6), 431–435. doi:10.1016/0370-2693(85)90460-5</ref> The possibility of standard model particles moving at faster-than-light speeds can be modeled using [[W:Lorentz invariance|Lorentz invariance]] violating terms, for example in the [[W:Standard-Model Extension|Standard-Model Extension]].<ref>Colladay, D.; Kostelecky, V. A. (1998). "Lorentz-Violating Extension of the Standard Model." *Physical Review D*, 58(11), 116002. doi:10.1103/PhysRevD.58.116002. arXiv:hep-ph/9809521</ref><ref>Kostelecky, V. A. (2004). "Gravity, Lorentz Violation, and the Standard Model." *Physical Review D*, 69(10), 105009. doi:10.1103/PhysRevD.69.105009. arXiv:hep-th/0312310</ref> In this framework, neutrinos experience [[W:Lorentz-violating neutrino oscillations|Lorentz-violating oscillations]] and can travel faster than light at high energies. This proposal was strongly criticized.<ref>Hughes, Richard J.; Stephenson, G. J. (1990). "Against Tachyonic Neutrinos." *Physics Letters B*, 244(1), 95–100. doi:10.1016/0370-2693(90)90275-B. https://zenodo.org/record/1258487</ref>
<br><br>

<br>
===3.1 Symbols===

{| class="wikitable"
|-
! Symbol !! Description !! style="width:2em;" | !! Symbol !! Description
|-
| <math>\alpha</math> || Coherent state amplitude || || <math>F</math> || Force
|-
| <math>\mathbf{A}</math> || Vector notation || || <math>G</math> || Conductance or Gain
|-
| <math>\chi</math> || Dispersive frequency shift || || <math>h</math> || Planck constant
|-
| <math>\Delta</math> || Tunneling rate or Detuning || || <math>I</math> || Electrical current
|-
| <math>\delta</math> || Dirac or Kronecker delta function || || <math>J</math> || Inductance
|-
| <math>\epsilon</math> || Energy asymmetry || || <math>K</math> || Number of Cooper pairs
|-
| <math>\eta</math> || Efficiency || || <math>p</math> || Probability or Probability density
|-
| <math>\Gamma</math> || Rate || || <math>r</math> || Measurement result
|-
| <math>\hbar</math> || Reduced Planck constant || || <math>R_q</math> || Resistance quantum
|-
| <math>\kappa</math> || Generalized eigenvalue or Cavity escape rate || || <math>S</math> || Noise spectral density or Scattering matrix
|-
| <math>\lambda</math> || Eigenvalue or Wavelength or Coupling constant || || <math>T</math> || Duration of time
|-
| <math>\mu</math> || Magnetic moment || || <math>V</math> || Voltage or Potential
|-
| <math>\omega</math> || Frequency || || <math>W</math> || Wiener random variable
|-
| <math>\Phi</math> || Magnetic flux || || <math>x,y,z</math> || Bloch coordinates
|-
| <math>\phi</math> || Phase || || <math>y</math> || Spherical harmonic
|-
| <math>\Phi_0</math> || Magnetic flux quantum || || <math>Z</math> || Impedance or Partition function
|-
| <math>\Pi</math> || Projection operator || || <math>\bar{A}</math> || Average of A
|-
| <math>\psi</math> || Quantum state || || <math>\mathcal{H}</math> || Stochastic Hamiltonian
|-
| <math>\tau_0</math> || Correlation time || || <math>\mathcal{L}</math> || Lindbladian or Lagrangian density
|-
| <math>\tau_m</math> || Characteristic measurement time || || <math>M</math> || Purity
|-
| <math>T</math> || Temperature || || <math>N</math> || Wigner-Smith time delay matrix
|-
| <math>\xi</math> || Langevin random variable || || <math>Q</math> || Accumulated charge
|-
| <math>^{*}</math> || Complex conjugate || || <math>R</math> || Signal-to-noise ratio
|-
| <math>^{\dagger}</math> || Hermitian conjugate || || <math>S</math> || Stochastic action
|-
| <math>A</math> || Amplitude || || <math>\mathcal{T}</math> || Time-ordering operator or Transmission
|-
| <math>\mathbf{B}</math> || Magnetic field || || <math>\Omega</math> || Kraus (or measurement) operator
|-
| <math>\beta</math> || Inverse temperature or Bhattacharyya coefficient or Concurrence || || <math>\hat{\rho}</math> || Density operator
|-
| <math>c</math> || Speed of light in a vacuum || || <math>\hat{\sigma}</math> || Unnormalized density operator or Pauli operator
|-
| <math>D</math> || Displacement operator or Bhattacharyya distance || || <math>\hat{a}</math> || Time-reversal operator
|-
| <math>d</math> || Degree of decoherence || || <math>a, b, \hat{e}</math> || Bosonic annihilation operators
|-
| <math>dW</math> || Wiener increment || || <math>\hat{H}</math> || Hamiltonian operator
|-
| <math>E</math> || POVM element or Electric field || || <math>l</math> || Lindblad operator
|-
| <math>e</math> || Electron charge or Euler's number || || <math>\hat{U}</math> || Unitary operator
|-
| <math>E_c</math> || Charging energy || || <math>\hat{X}, \hat{P}</math> || Quadrature operators
|-
| <math>E_F</math> || Fermi energy || || <math>\hat{O}</math> || Operator or Observable
|-
| <math>E_J</math> || Josephson energy || ||
|}

== 4. Fundamental Particles (Standard Model) ==
[[File:Standard Model of Elementary Particles.svg|thumb|Standard Model of elementary particles]]
The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetic, weak and strong interactions – excluding gravity) in the universe and classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists worldwide.with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks. Since then, proof of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.
<br><br>

{| class="wikitable"
|+ Standard Model particles
|-
! Category !! Particles !! Count
|-
| Quarks || up, down, charm, strange, top, bottom || 6<ref name="PDG"/>
|-
| Antiquarks || anti‑up, anti‑down, anti‑charm, anti‑strange, anti‑top, anti‑bottom || 6<ref name="PDG"/>
|-
| Leptons || electron, muon, tau, neutrinos || 6<ref name="Fermilab"/>
|-
| Antileptons || positron, anti‑muon, anti‑tau, anti‑neutrinos || 6<ref name="Fermilab"/>
|-
| '''Total fermions''' || || 24<ref name="PDG"/>
|-
| Bosons || photon, gluon, W+, W−, Z0, Higgs || 6<ref name="CERN"/>
|-
| Gravity (theoretical) || graviton || 1<ref name="CERN"/>
|-
| '''Total bosons''' || || 7<ref name="CERN"/>
|-
| '''Grand total''' || || 31–32<ref name="CERN"/>
|}

=== 4.1 Key Formulas ===

* Fermions: <math>6 + 6 + 6 + 6 = 24</math><ref name="PDG" />  

* Standard Model total: <math>24 + 6 + 1 = 31</math><ref name="CERN" />  

* Baryon structure: <math>3 quarks</math><ref name="PDG" />  

* Meson structure: <math>1 quark + 1 antiquark</math><ref name="PDG" />

== 5. Composite Particles (Hadron Zoo) ==
{| class="wikitable"
|+ Hadrons, mesons, exotic states
! Type
! Examples
! Notes
|-
| Baryons
| proton, neutron, Δ, Σ, Ξ, Ω
| 3 quarks <ref name="IUPAC"/>
|-
| Mesons
| π, K, η, ρ
| 1 quark + 1 antiquark <ref name="CERN"/> 
|-
| Exotic
| tetraquarks, pentaquarks
| 4 or 5 quark states <ref name="PDG"/> 
|-
| Resonances
| many
| short-lived states<ref name="Fermilab"/>
|}

==5.1 Quarks==

<!-- FIRST TABLE FLOATS RIGHT: BARYONS -->
<div style="float:right; width:60%; margin-left:1em;">
{| class="wikitable" style="width:100%; text-align:center; table-layout:fixed;"
|+ Baryon angular momentum quantum numbers {{nobr|for {{math|''L'' {{=}} 0, 1, 2, 3 }} }}
|-
! Spin,<br>''S''
! Orbital angular<br>momentum, ''L''
! Total angular<br>momentum, ''J''
! [[#Parity|Parity]],<br>''P''
! Condensed<br>notation, ''J''<sup>''P''</sup>
|-
|rowspan="4"| {{sfrac|1|2}}
| 0 || {{sfrac|1|2}} || + || {{sfrac|1|2}}<sup>+</sup>
|-
| 1 || {{sfrac|3|2}}, {{sfrac|1|2}} || − || {{sfrac|3|2}}<sup>−</sup>, {{sfrac|1|2}}<sup>−</sup>
|-
| 2 || {{sfrac|5|2}}, {{sfrac|3|2}} || + || {{sfrac|5|2}}<sup>+</sup>, {{sfrac|3|2}}<sup>+</sup>
|-
| 3 || {{sfrac|7|2}}, {{sfrac|5|2}} || − || {{sfrac|7|2}}<sup>−</sup>, {{sfrac|5|2}}<sup>−</sup>
|-
|rowspan="4"| {{sfrac|3|2}}
| 0 || {{sfrac|3|2}} || + || {{sfrac|3|2}}<sup>+</sup>
|-
| 1 || {{sfrac|5|2}}, {{sfrac|3|2}}, {{sfrac|1|2}} || − || {{sfrac|5|2}}<sup>−</sup>, {{sfrac|3|2}}<sup>−</sup>, {{sfrac|1|2}}<sup>−</sup>
|-
| 2 || {{sfrac|7|2}}, {{sfrac|5|2}}, {{sfrac|3|2}}, {{sfrac|1|2}} || + || {{sfrac|7|2}}<sup>+</sup>, {{sfrac|5|2}}<sup>+</sup>, {{sfrac|3|2}}<sup>+</sup>, {{sfrac|1|2}}<sup>+</sup>
|-
| 3 || {{sfrac|9|2}}, {{sfrac|7|2}}, {{sfrac|5|2}}, {{sfrac|3|2}} || − || {{sfrac|9|2}}<sup>−</sup>, {{sfrac|7|2}}<sup>−</sup>, {{sfrac|5|2}}<sup>−</sup>, {{sfrac|3|2}}<sup>−</sup>
|}
<!-- MESON TABLE FLOATS RIGHT INSIDE TEXT BLOCK -->
<div style="float:right; width:50%; margin:0 0 1em 1em;">
{| class="wikitable" style="width:100%; text-align:center; table-layout:fixed;"
|+ Meson angular momentum quantum numbers for {{mvar|L}} = 0, 1, 2, 3
|-
! {{mvar|S}}
! {{mvar|L}}
! {{math|P}}
! {{mvar|J}}
! {{mvar|J}}{{sup|{{math|P}}}}
|-
|rowspan="4"| 0
| 0 || − || 0 || 0{{sup|−}}
|-
| 1 || + || 1 || 1{{sup|+}}
|-
| 2 || − || 2 || 2{{sup|−}}
|-
| 3 || + || 3 || 3{{sup|+}}
|-
|rowspan="4"| 1
| 0 || − || 1 || 1{{sup|−}}
|-
| 1 || + || 2, 0 || 2{{sup|+}}, 0{{sup|+}}
|-
| 2 || − || 3, 1 || 3{{sup|−}}, 1{{sup|−}}
|-
| 3 || + || 4, 2 || 4{{sup|+}}, 2{{sup|+}}
|}
</div>
</div>

<!-- TEXT BLOCK FLOWS LEFT AND UNDER MESON TABLE -->
<div>
A '''tetraquark''' is an [[W:exotic meson|exotic meson]] composed of four valence [[W:quark|quark]]s. A tetraquark state has long been suspected to be allowed by quantum chromodynamics,<ref>{{ cite journal|author1=U. Kulshreshtha|author2=D. S. Kulshreshtha|author3=J. P. Vary|title= Hamiltonian, path integral and BRST formulations of large ''N'' scalar QCD<sub>2</sub> on the light-front and spontaneous symmetry breaking|journal=[[W:European Physical Journal C|European Physical Journal C]]|volume= 75|issue= 4|page= 1|European Physical Journal C74|year=2015|doi=10.1140/epjc/s10052-015-3377-x|arxiv=1503.06177|bibcode=2015EPJC...75..174K|s2cid=119102254 }}</ref> the modern theory of strong interactions. A tetraquark state is an example of an exotic hadron that lies outside the conventional quark model classification. A number of different types of tetraquark have been observed.<br> Several tetraquark candidates have been reported by particle physics experiments in the 21st century. The quark contents of these states are almost all q{{overline|q}}Q{{overline|Q}}, where q represents a light ([[W:up quark|up]], [[W:down quark|down]] or [[W:strange quark|strange]]) quark, Q represents a heavy ([[W:charm quark|charm]] or [[W:bottom quark|bottom]]) quark, and antiquarks are denoted with an overline. The existence and stability of tetraquark states with the qq{{overline|Q}}{{overline|Q}} (or {{overline|q}}{{overline|q}}QQ) have been discussed by theoretical physicists for a long time, however these are yet to be reported by experiments.<ref>{{cite journal|last1=Si-Qiang|first1=Luo|last2=Kan|first2=Chen|last3=Xiang|first3=Liu|last4=Yan-Rui|first4=Liu|last5=Shi-Lin|first5=Zhu|title=Exotic tetraquark states with the ''qq{{overline|Q}}{{overline|Q}}'' configuration|journal=European Physical Journal C|date=25 October 2017|volume=77:709|issue=10|url=https://link.springer.com/content/pdf/10.1140%2Fepjc%2Fs10052-017-5297-4.pdf|access-date=26 November 2017|doi=10.1140/epjc/s10052-017-5297-4|s2cid=119377466|doi-access=free}}</ref><br> A particle temporarily called [[W:X(3872)|X(3872)]], by the [[W:Belle experiment|Belle experiment]] in Japan, was proposed to be a tetraquark candidate,<ref> {{cite web |author=D. Harris |date=13 April 2008 |title=The charming case of X(3872) |url=http://www.symmetrymagazine.org/breaking/2008/04/13/the-charming-case-of-x3872/ |work=[[W:Symmetry Magazine|Symmetry Magazine]] |access-date=2009-12-17 }}</ref> as originally theorized.<ref> {{cite journal|author1=L. Maiani|author2=F. Piccinini|author3=V. Riquer|author4=A.D. Polosa|year=2005|title=Diquark-antidiquarks with hidden or open charm and the nature of X(3872)|journal=[[W:Physical Review D|Physical Review D]]|volume=71|issue=1|arxiv=hep-ph/0412098|bibcode=2005PhRvD..71a4028M|doi=10.1103/PhysRevD.71.014028|article-number=014028|s2cid=119345314}}</ref>
The name X is a temporary name, indicating that there are still some questions about its properties to be tested. The number following is the mass of the particle in  [[W:Mass|MeV/c²]]
<br><br><br>
[[File:TQ EB ape hyp r1 8 r2 14 Act 3D Sim.jpg|thumb|300px|upright=1.2|Colour flux tubes produced by four static quark and antiquark charges, computed in lattice QCD.<ref>{{Cite web |date=2008-04-13 |title=The charming case of X(3872) (APS April 2008) {{!}} symmetry magazine |url=https://www.symmetrymagazine.org/breaking/2008/04/13/the-charming-case-of-x3872?language_content_entity=und |access-date=2023-11-09 |website=www.symmetrymagazine.org |language=en}}</ref> Confinement in quantum chromodynamics leads to the production of flux tubes connecting colour charges. The flux tubes act as attractive QCD string-like potentials.]]
<br>



A '''pentaquark''' is a [[W:subatomic particle|subatomic particle]], consisting of four [[W:quark|quark]]s and one [[W:antiquark|antiquark]] bound together. Evidence for the existence of pentaquarks has been found. As quarks have a baryon number of {{sfrac|+|1|3}}, and antiquarks of {{sfrac|−|1|3}}, the pentaquark would have a total baryon number of 1, and thus would be a [[W:baryon|baryon]]. Further, because it has five quarks instead of the usual three found in regular baryons (A.k.a. "triquarks"), it is classified as an [[W:exotic baryon|exotic baryon]]. The name pentaquark was coined by Claude Gignoux ''et al.'' (1987)<ref> {{cite journal |last1=Gignoux |first1=C. |last2=Silvestre-Brac |first2=B. |last3=Richard |first3=J.M. |date=1987-07-16 |title=Possibility of stable multiquark baryons |journal=Physics Letters&nbsp;B |volume=193 |issue=2 |pages=323–326 |doi=10.1016/0370-2693(87)91244-5 |bibcode=1987PhLB..193..323G }} </ref> and [[W:Harry J. Lipkin|Harry J. Lipkin]] in 1987; however, the possibility of five-quark particles was identified as early as 1964 when [[W:Murray Gell-Mann|Murray Gell-Mann]] first postulated the [[W:quark model|existence of quarks]]. Although predicted for decades, pentaquarks proved surprisingly difficult to discover and some physicists were beginning to suspect that an unknown law of nature prevented their production.
</div>

<div style="clear:both;"></div>

== 5.2 Tachyon ==
[[File:Faster than light implies time travel diagram.svg|thumb|upright=1|[[W:Spacetime diagram|Spacetime diagram]] showing that moving faster than light implies time travel in the context of special relativity. A spaceship departs from Earth from A to C slower than light. At B, Earth emits a tachyon, which travels faster than light but forward in time in Earth's reference frame. It reaches the spaceship at C. The spaceship then sends another tachyon back to Earth from C to D. This tachyon also travels forward in time in the spaceship's reference frame. This effectively allows Earth to send a signal from B to D, back in time.]]
* This section is about hypothetical faster-than-light particles. For quantum fields with imaginary mass, see [[W:Tachyonic field|tachyonic field]]s.

A '''tachyon''' (or tachyonic particle) is a hypothetical type of particle that would move only at speeds faster than light. Modern physics, however, rules out the existence of such faster-than-light particles because they conflict with established physical laws. Relativity rules out speeds faster than light.<ref>Tipler, Frank J. (2008). ''Modern Physics'', 5th edition. W.H. Freeman & Co., New York, NY, p. 54. ISBN 978-0-7167-7550-8. Quote: "...so existence of particles v > c ... Called 'tachyons' ... would present relativity with serious ... problems of infinite creation energies and causality paradoxes."</ref><ref>Randall, Lisa (2005). ''Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions''. Harper Collins, p. 286. ISBN 978-0-06-053108-9. Quote: "People initially thought of tachyons as particles traveling faster than the speed of light ... But we now know that a tachyon indicates an instability in a theory that contains it. Regrettably, for science fiction fans, tachyons are not real physical particles that appear in nature."</ref> If tachyons were real, they might allow information to be transmitted faster than light, possibly even backward in time, That would violate causality and create logical contradictions such as the grandfather paradox.<ref>Tipler, Frank J. (2008). ''Modern Physics'', 5th edition. W.H. Freeman & Co., New York, NY, p. 54.</ref>

In theory, tachyons would behave weird: their speed would increase as their energy decreased, and bringing them down to the speed of light would require infinite energy, effectively making them the “inverse” of the usual  <math>E=MC^2</math> relationship. No experiment has ever produced reliable evidence for their existence.

The name ''tachyon'' originates from a 1967 paper by Gerald Feinberg, who studied quantum-field excitations with an imaginary mass. Later research showed that these excitations do not correspond to real faster-than-light particles, though physicists still use the term “tachyon” in contexts such as tachyon condensation, where it refers to unstable or imaginary-mass fields rather than actual particles.<br>
As noted by [[Albert Einstein]], [[W:Richard C. Tolman|Richard C. Tolman]], [[special relativity]] implies that faster-than-light particles, if they existed, [[W:Tachyonic antitelephone|could be used to communicate backwards in time]].<ref>Benford, G.; Book, D.; Newcomb, W. (1970). "The Tachyonic Antitelephone". *Physical Review D*, 2(2): 263–265. doi:10.1103/PhysRevD.2.263.</ref>

== 6. Graph Example ==
[[File:Standard Model of Elementary Particles.svg|thumb|right|400px]]
The Standard Model of particle physics is describing a part of the known fundamental forces (Weak and strong interactions electromagnetic– not including [[W:Gravity|gravity]] in the universe and containing all known elementary particles.<ref name="CERN"/> Developed in the second half of the 20th century, by many scientists worldwide, with the current formulas finalized in the middle of 1970. Experiments proof of the existence of quarks. Proof of the top quark (1994), the tau neutrino (2001), and the Higgs boson (2013) have added to the Standard Model.<ref name="PDG"/> The Standard Model  predicted various properties of weak  currents and the W and Z bosons.<ref name="CERN"/>

Standard Model is theoretically self-consistent and has some success in providing predictions, Some unexplained physical phenomena make it to fall short of being a complete theory of fundamental interactions. It does not explain why there is more matter than anti-matter. The full theory of gravitation as per general relativity, account for the universe's expansion as may be described by [[W:dark energy|dark energy]]. This model not contains any viable dark matter particle that has all of the properties found from observational cosmology. It also does not has neutrino oscillations and their masses.<ref name="PDG"/>

The Standard Model is used by theoretical and experimental particle physicists. The Standard Model is basis of a quantum field theory, exhibiting lots of phenomena, including  symmetry breaking, anomalies, and different behavior. It is a basis for more exotic models for hypothetical particles, [[W:Multidimensional scaling|Multidimensional scaling]], and symmetries and [[W:Supersymmetry|supersymmetry]], to see  results at with the Standard Model, such [[W:Neutrino oscillation|neutrino oscillations]] and [[W:Dark matter|dark matter]].<ref name="CERN"/>

== 7. Simple Explanation for Kids ==
Everything around us  your toys, the air, even you, is made of tiny building blocks called **particles**.<ref name="Fermilab"/>  At the smallest level, these particles combine in fun ways to form atoms, molecules, and more.<ref name="IUPAC"/>

{| class="wikitable"
|-
! style="width:160px;" | Image !! What It Means
|-
| [[File:Simple_atom.png|thumb|150px|A very simple atom]] || This shows an atom with a nucleus in the center and electrons around it. Atoms are like LEGO bricks of the universe.
|-
| [[File:Quark_structure_proton.svg|thumb|150px|Quark structure of a proton]] || A proton has three quarks: two "up" quarks (u) and one "down" quark (d). The colors of the quarks in the diagram help show that up and down quarks are different types. In real physics, quarks also have a property called “color charge” (red, green, blue) that keeps them stuck together.<ref name="PDG"/>
|-
| [[File:Quark_structure_neutron.svg|thumb|150px|Quark structure of a neutron]] || A neutron has one "up" quark and two "down" quarks. Again, the color coding shows the difference between the types of quarks, and each quark also has a color charge that helps hold the neutron together.<ref name="PDG"/>
|}

Here’s how to think about it:  

* Atoms are like tiny LEGO bricks.  
* Inside protons and neutrons are quarks, even smaller building blocks.<ref name="PDG"/>
* Quarks are glued together by the strong force.<ref name="PDG"/>
* Diagrams use colors to show different quark types (up vs down) and their “color charge” (red, green, blue).  
* Protons and neutrons stick together in the nucleus, while electrons orbit around it.  
* Molecules form when atoms join, making everything you see.  
* Learning about these tiny pieces helps us understand why matter behaves the way it does and how the universe is built.

== 8. Advanced Explanation ==
{| class="wikitable"
|+ Particle fields
|-
! Particle !! Field
|-
| Electron || electron field<ref name="Fermilab"/>
|-
| Up quark || up‑quark field<ref name="PDG"/>
|-
| Photon || electromagnetic field<ref name="CERN"/>
|-
| Higgs boson || Higgs field<ref name="CERN"/>
|}
===8.1 Electron===
[[File:Electron-orbital-magnetic-moment-simplified.svg|thumb|Electron-orbital-magnetic-moment-simplified]]
The electron <math>e^-</math>, or <math>\beta^-</math> in nuclear reactions is a negatively charged [[W:subatomic particle|subatomic particle]] and an [[W:elementary particle|elementary particle]] that, with [[W:up quark|up quark]]s and [[W:down quark|down quark]]s, forms ordinary matter.<br>
Electrons are very light and occupy [[W:atomic orbital|orbitals]] around a [[W:atomic nucleus|atomic nucleus]]. Their arrangement defines an atom’s [[W:chemical properties|chemical properties]], with outer [[W:valence electron|valence electron]] forming [[W:chemical bond|chemical bond]]s and driving [[W:chemical reaction|chemical reaction]]s, while inner electrons make up the [[W:atomic core|atomic core]].
<br>In [[W:metal|metal]]s, delocalised electrons allow high [[W:electrical conductivity|electrical]] and [[W:thermal conduction|thermal]] conductivity. In [[W:semiconductor|semiconductor]]s, electron and [[W:electron hole|hole]] numbers can be tuned by doping, temperature, voltage, or radiation, enabling [[electronics]].<br>
Free electrons in [[W:vacuum|vacuum]]s can be accelerated and focused for applications like [[W:cathode ray tube|cathode ray tube]]s, [[W:electron microscope|electron microscope]]s, [[W:electron beam welding|electron beam welding]], [[W:lithography|lithography]], and [[W:particle accelerator|particle accelerator]]s producing [[W:synchrotron radiation|synchrotron radiation]].

===8.2 Up quark===
[[File:Quark wiki.jpg|thumb|Quark_wiki]]
The up quark (symbol: 
𝑢) is the lightest quark and one of the basic building blocks of [[W:matter|matter]].
Together with the [[W:down quark|down quark]], it makes up [[W:proton|protons]] and [[W:neutron|neutrons]]: 
* A [[W:proton|proton]] is two up quarks + one down quark: <math>uud</math> 
* A [[W:neutron|neutron]] is one up quark + two down quarks: <math>udd</math>
It belongs to the first and lightest family of quarks. It has
an electric charge of <math>+2/3,e</math> (twice the charge of a down quark, but only 2/3 of an electron’s charge)
a very tiny mass, about <math>2.2,\mathrm{MeV}/c^2</math> (roughly 1/2000 the mass of a proton). 
Like all quarks, it has spin <math>1/2</math> (making it a [[W:fermion|fermion]]) and experiences all four fundamental forces: [[W:gravitation|gravitation]], [[W:electromagnetism|electromagnetism]], the [[W:weak interaction|weak force]], and the [[W:strong interaction|strong nuclear force]].
Its antiparticle is the [[W:up antiquark|anti-up quark]]; it has the same properties except that its charge is <math>-2/3,e</math> and a few other properties are reversed.
The existence of the up quark (along with [[W:down quark|down]] and [[W:strange quark|strange quarks]]) was proposed in 1964 by [[W:Murray Gell-Mann|Murray Gell-Mann]] and [[W:George Zweig|George Zweig]] to explain observed patterns in subatomic particles. It was first directly observed in experiments at [[W:Stanford Linear Accelerator Center|Stanford Linear Accelerator Center]] in 1968.

===8.3 Photon===
[[File:Photon model.png|thumb|Photon_model]]
A photon (Greek φωτός), [[W:light|light]] is an [[W:elementary particle|elementary particle]] that is a [[W:quantum|quantum]] of the [[W:electromagnetic field|electromagnetic field]], including [[W:electromagnetic radiation|electromagnetic radiation]] such as [[W:light|light]] and [[W:radio wave|radio wave]]s, and the [[W:force carrier|force carrier]] for the [[W:electromagnetic force|electromagnetic force]].<br>
Photons are [[W:massless particle|massless]] and can move only at one speed: the <math>c</math>, the [[W:speed of light|speed of light]] in vacuum. The photon belongs to the class of [[W:boson|boson]] particles.<br>The photon has no [[W:electric charge|electric charge]],<ref>{{cite book |last1=Frisch |first1=David H. |title=Elementary Particles |last2=Thorndike |first2=Alan M. |publisher=[[W:David Van Nostrand|David Van Nostrand]] |year=1964 |location=Princeton, New Jersey |page=22 |language=en-us |author1-link=W:David H. Frisch}}</ref><ref name="chargeless">{{cite journal |last1=Kobychev |first1=V. V. |last2=Popov |first2=S. B. |year=2005 |title=Constraints on the photon charge from observations of extragalactic sources |journal=[[W:Astronomy Letters|Astronomy Letters]] |volume=31 |issue=3 |pages=147–151 |arxiv=hep-ph/0411398 |bibcode=2005AstL...31..147K |doi=10.1134/1.1883345 |s2cid=119409823}}</ref> is generally considered to have zero [[W:rest mass|rest mass]],<ref>{{cite web |first=John |last=Baez |author-link=W:John Baez |title=What is the mass of a photon? |publisher=[[W:University of California, Riverside|U.C. Riverside]] |type=pers. academic site |url=http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html |access-date=2009-01-13 |archive-date=2014-05-31 |archive-url=https://web.archive.org/web/20140531100537/http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html |url-status=live }}</ref> and is a [[W:stable particle|stable particle]]. The experimental upper limit on the photon mass<ref>{{Cite journal |last1=Tu |first1=Liang-Cheng |last2=Luo |first2=Jun |last3=Gillies |first3=George T |date=2005-01-01 |title=The mass of the photon |url=https://iopscience.iop.org/article/10.1088/0034-4885/68/1/R02 |journal=Reports on Progress in Physics |volume=68 |issue=1 |pages=77–130 |doi=10.1088/0034-4885/68/1/R02 |bibcode=2005RPPh...68...77T |issn=0034-4885|url-access=subscription }}</ref><ref>{{Cite journal |last1=Goldhaber |first1=Alfred Scharff |last2=Nieto |first2=Michael Martin |date=2010-03-23 |title=Photon and graviton mass limits |url=https://link.aps.org/doi/10.1103/RevModPhys.82.939 |journal=Reviews of Modern Physics |language=en |volume=82 |issue=1 |pages=939–979 |doi=10.1103/RevModPhys.82.939 |issn=0034-6861 |arxiv=0809.1003 |bibcode=2010RvMP...82..939G |access-date=2024-02-01 |archive-date=2024-05-13 |archive-url=https://web.archive.org/web/20240513012520/https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.82.939 |url-status=live }}</ref> is very small, on the order of 10<sup>−53</sup> g; its lifetime would be more than 10<sup>18</sup> years.<ref>{{Cite journal |last=Heeck |first=Julian |date=2013-07-11 |title=How Stable is the Photon? |url=https://link.aps.org/doi/10.1103/PhysRevLett.111.021801 |journal=Physical Review Letters |language=en |volume=111 |issue=2 |article-number=021801 |doi=10.1103/PhysRevLett.111.021801 |pmid=23889385 |issn=0031-9007 |arxiv=1304.2821 |bibcode=2013PhRvL.111b1801H |access-date=2024-02-01 |archive-date=2024-05-13 |archive-url=https://web.archive.org/web/20240513012534/https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111.021801 |url-status=live }}</ref>

===8.4 Higgs field===

[[File:CMS Higgs-event.jpg|thumb|CMS_Higgs-event]]
The Higgs field is an invisible field that permeates all of space, giving mass to elementary particles that interact with it. Particles gain mass by interacting with the field, much like a person moving through mud. The more a particle interacts with the Higgs field, the more mass it has. The existence of this field was confirmed by the discovery of the Higgs boson, which is an excitation or ripple in the field.
* '''Mass:''' The Higgs field is a medium that particles move through: Particles that interact strongly with the Higgs field are “slowed down” → they behave as if they have larger mass. Particles that interact weakly get small mass. Particles that do not interact at all (like photons) remain massless.This interaction is not friction; it’s a fundamental quantum interaction.
* '''The Higgs boson:''' Is a ripple (excitation) in the Higgs field. Discovered in 2012 at CERN. Its existence confirmed the mechanism that gives particles mass.
* '''Mechanism:''' The interaction between a particle and the field is what gives the particle its mass. It is a fundamental concept in the Standard Model of particle physics that explains why some particles have mass and others do not. 
=== Gauge symmetries: ===

=== <math>U(1)</math> Electromagnetism<ref name="CERN" />  ===

* <math>SU(2)</math> Weak force<ref name="CERN" />  

* <math>SU(3)</math> Strong force<ref name="CERN" />

== 9. Summary Table ==
{| class="wikitable"
|-
! Category !! Count !! Notes
|-
| [[W:Chemical element|Chemical elements]] || 118 || Periodic table<ref name="IUPAC"/>
|-
| [[W:Elementary particle|Fundamental particles]] || 31–32 || Standard Model<ref name="CERN"/>
|-
| [[W:Subatomic particles|Subatomic particles]] || Dozens || Commonly observed<ref name="Fermilab"/>
|-
| [[W:List_of_particles#Composite_particles|Composite particles]] || 400+ || Hadrons, mesons, exotic states<ref name="PDG"/>
|-
| [[W:Boson|Bosons]] || 6 confirmed || Photon, gluon, W+, W−, Z0, Higgs<ref name="CERN"/>
|-
| [[W:Fermion|Fermions]] || 24 || Quarks + leptons + antiparticles<ref name="PDG"/>
|}

===External links===
* [https://pdg.lbl.gov Particle Data Group – Particle Listings] <ref name="PDG">Particle Data Group. "Particle Listings." https://pdg.lbl.gov</ref>
* [https://home.cern/science/physics/standard-model CERN – Standard Model overview] <ref name="CERN">CERN. "The Standard Model of Particle Physics." https://home.cern/science/physics/standard-model</ref>
* [https://iupac.org/what-we-do/periodic-table-of-elements/ IUPAC – Periodic Table of Elements] <ref name="IUPAC">IUPAC. "Periodic Table of Elements." https://iupac.org/what-we-do/periodic-table-of-elements/</ref>
* [https://www.fnal.gov Fermilab – Quarks and Leptons] <ref name="Fermilab">Fermilab. "Quarks and Leptons." https://www.fnal.gov</ref>

==See also==
{{:Quantum/See also}}

=10. References=
{{reflist}}

== 11. Navigation Box ==
<div>
{{Navbox
| name = MatterLevels
| title = Levels of Matter
| state = expanded
| list1 = [[Chemical element]] · [[W:Atom|Atom]] · [[W:Subatomic particle|Subatomic particle]] · [[W:Quark|Quark]] · [[W:Lepton|Lepton]] · [[W:Boson|Boson]] · [[W:Hadron|Hadron]] · [[W:Standard Model|Standard Model]]
}}
</div>
[[Category:Quantum mechanics]]
[[Category:Quantum physics]]
[[Category:Particle physics]]