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Scalar boson

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Boson with spin equal to zero

Standard Model ofparticle physics
Elementary particles of the Standard Model
Background Particle physics Standard Model Quantum field theory Gauge theory Spontaneous symmetry breaking Higgs mechanism
Constituents Electroweak interaction Quantum chromodynamics CKM matrix Standard Model mathematics
Limitations Strong CP problem Hierarchy problem Neutrino oscillations Physics beyond the Standard Model
Scientists Rutherford Thomson Chadwick Bose Sudarshan Davis Jr Anderson Fermi Dirac Feynman Rubbia Gell-Mann Kendall Taylor Friedman Powell Anderson Glashow Iliopoulos Lederman Maiani Meer Cowan Nambu Chamberlain Cabibbo Schwartz Perl Majorana Weinberg Lee Ward Salam Kobayashi Maskawa Mills Yang Yukawa 't Hooft Veltman Gross Pais Pauli Politzer Reines Schwinger Wilczek Cronin Fitch Vleck Higgs Englert Brout Hagen Guralnik Kibble de Mayolo Lattes Zweig
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Ascalar boson is aboson whosespin equals zero.^[1] Aboson is a particle whosewave function issymmetric under particle exchange and therefore followsBose–Einstein statistics. Thespin–statistics theorem implies that all bosons have an integer-valuedspin.^[2]Scalar bosons are the subset of bosons with zero-valued spin.

The namescalar boson arises fromquantum field theory, which demands that fields of spin-zero particles transform like a scalar underLorentz transformation (i.e. areLorentz invariant).

Apseudoscalar boson is a scalar boson that has oddparity, whereas "regular" scalar bosons have even parity.^[3]

The only fundamental scalar boson in theStandard Model ofparticle physics is theHiggs boson,^[1] the existence of which was confirmed on 14 March 2013 at theLarge Hadron Collider by CMS and ATLAS.^[4] As a result of this confirmation, the 2013Nobel Prize in Physics was awarded toPeter Higgs andFrançois Englert.^[5]
Various known composite particles are scalar bosons, e.g. thealpha particle andscalar mesons.^[6]
Theφ⁴-theory orquartic interaction is a popular "toy model" quantum field theory that uses scalar bosonic fields, used in many introductory quantum textbooks^[7]^{[page needed]} to introduce basic concepts in field theory.

There are no fundamentalpseudoscalars in the Standard Model, but there are severalpseudoscalar mesons, like thepion.^[8]

^^a ^b"The scalar boson". ATLAS Collaboration. March 26, 2015. RetrievedMay 22, 2021.
^Nave, R."Spin classification of particles". RetrievedJune 8, 2021.
^Thomson, Mark (2011)."Handout 9: The Weak Interaction and V-A"(PDF). RetrievedJune 6, 2021.
^"New results indicate that particle discovered at CERN is a Higgs boson" (Press release). 14 March 2013. Retrieved22 May 2021.
^"The Nobel Prize in Physics for 2013" (Press release). Nobel Media AB. 2013. Retrieved22 May 2021.
^Qaim, Syed M.; Spahn, Ingo; Scholten, Bernhard; Neumaier, Bernd (8 June 2016)."Uses of alpha particles, especially in nuclear reaction studies and medical radionuclide production".Radiochimica Acta.104 (9): 601.doi:10.1515/ract-2015-2566.S2CID 56100709. Retrieved22 May 2021.
^Peskin, Michael E.; Schroeder, Daniel V. (1995).An Introduction to Quantum Field Theory. Westview Press.ISBN 978-0-201-50397-5.
^Nave, R. (c. 2010)."Hadrons, baryons, mesons".HyperPhysics. Atlanta, GA:Georgia State University, Department of Physics and Astronomy. Retrieved23 May 2021 – via hyperphysics.phy-astr.gsu.edu.

Quarks	Up (quark antiquark) Down (quark antiquark) Charm (quark antiquark) Strange (quark antiquark) Top (quark antiquark) Bottom (quark antiquark)
Leptons	Electron Positron Muon Antimuon Tau Antitau Neutrino Electron neutrino Electron antineutrino Muon neutrino Muon antineutrino Tau neutrino Tau antineutrino

Gauge	Photon Gluon W and Z bosons
Scalar	Higgs boson

Gauginos	Gluino Gravitino Photino
Others	Axino Chargino Higgsino Neutralino Sfermion (Stop squark)

Others

Baryons	Nucleon Proton Antiproton Neutron Antineutron Delta baryon Lambda baryon Sigma baryon Xi baryon Omega baryon
Mesons	Pion Rho meson Eta and eta prime mesons Bottom eta meson Phi meson J/psi meson Omega meson Upsilon meson Kaon B meson D meson Quarkonium
Exotic hadrons	Tetraquark (Double-charm tetraquark) Pentaquark