{{Short description|Boson with spin equal to zero}} {{Standard model of particle physics}} A '''scalar boson''' is a boson whose spin equals zero.<ref name=Atlas>{{cite web|url=https://atlas.cern/updates/briefing/scalar-boson|title=The scalar boson|date=March 26, 2015|access-date=May 22, 2021|publisher=ATLAS Collaboration}}</ref> A ''boson'' is a particle whose wave function is symmetric under particle exchange and therefore follows Bose–Einstein statistics. The spin–statistics theorem implies that all bosons have an integer-valued spin.<ref>{{cite web|url=http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/spinc.html|title=Spin classification of particles|first=R.|last=Nave|access-date=June 8, 2021}}</ref> ''Scalar'' bosons are the subset of bosons with zero-valued spin.
The name ''scalar boson'' arises from quantum field theory, which demands that fields of spin-zero particles transform like a scalar under Lorentz transformation (i.e. are Lorentz invariant).
A '''pseudoscalar boson''' is a scalar boson that has odd parity, whereas "regular" scalar bosons have even parity.<ref>{{cite web|url=https://www.hep.phy.cam.ac.uk/~thomson/partIIIparticles/handouts/Handout_9_2011.pdf|title=Handout 9: The Weak Interaction and V-A|first=Mark|last=Thomson|date=2011|access-date=June 6, 2021}}</ref>
== Examples == === Scalar === * The only fundamental scalar boson in the Standard Model of particle physics is the Higgs boson,<ref name=Atlas/> the existence of which was confirmed on 14 March 2013 at the Large Hadron Collider by CMS and ATLAS.<ref> {{cite press release |title = New results indicate that particle discovered at CERN is a Higgs boson |date = 14 March 2013 |url = https://home.cern/news/press-release/cern/new-results-indicate-particle-discovered-cern-higgs-boson |access-date = 22 May 2021 }} </ref> As a result of this confirmation, the 2013 Nobel Prize in Physics was awarded to Peter Higgs and François Englert.<ref> {{cite press release |title = The Nobel Prize in Physics for 2013 |publisher = Nobel Media AB |year = 2013 |url = https://www.nobelprize.org/prizes/physics/2013/summary/ |access-date=22 May 2021 }} </ref> * Various known composite particles are scalar bosons, e.g. the alpha particle and scalar mesons.<ref> {{cite journal |last1=Qaim |first1=Syed M. |last2=Spahn |first2=Ingo |last3=Scholten |first3=Bernhard |last4=Neumaier |first4=Bernd |date=8 June 2016 |title=Uses of alpha particles, especially in nuclear reaction studies and medical radionuclide production |journal=Radiochimica Acta |volume=104 |issue=9 |page=601 |doi=10.1515/ract-2015-2566 |s2cid=56100709 |url=https://www.degruyter.com/document/doi/10.1515/ract-2015-2566/html |access-date=22 May 2021 |url-access=subscription }} </ref> * The ''φ''<sup>4</sup>-theory or ''quartic interaction'' is a popular "toy model" quantum field theory that uses scalar bosonic fields, used in many introductory quantum textbooks<ref> {{cite book |first1 = Michael E. |last1 = Peskin |first2 = Daniel V. |last2 = Schroeder |year = 1995 |title = An Introduction to Quantum Field Theory |publisher = Westview Press |isbn = 978-0-201-50397-5 |url = https://archive.org/details/introductiontoqu0000pesk |url-access = registration }} </ref>{{page needed|date=January 2017}} to introduce basic concepts in field theory.
=== Pseudoscalar === * There are no fundamental pseudoscalars in the Standard Model, but there are several pseudoscalar mesons, like the pion.<ref>{{cite web |first=R. |last=Nave |date=c. 2010 |title=Hadrons, baryons, mesons |website=HyperPhysics |publisher=Georgia State University, Department of Physics and Astronomy |place=Atlanta, GA |url=http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/hadron.html |via=hyperphysics.phy-astr.gsu.edu |access-date=23 May 2021 }}</ref>
== See also == * Scalar field theory * Klein–Gordon equation * Vector boson * Higgs boson
{{clear}} == References == {{reflist|25em}}
{{Particles}}
{{DEFAULTSORT:Scalar Boson}} Category:Bosons Category:Quantum field theory Category:Subatomic particles with spin 0