Scalar boson
{{Short description|Boson with spin equal to zero}}
{{Standard model of particle physics}}
A scalar boson is a boson whose spin equals zero.{{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}} 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.{{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}} 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.{{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}}
Examples
= Scalar =
- The only fundamental scalar boson in the Standard Model of particle physics is the Higgs boson, the existence of which was confirmed on 14 March 2013 at the Large Hadron Collider by CMS and ATLAS.
{{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
}}
As a result of this confirmation, the 2013 Nobel Prize in Physics was awarded to Peter Higgs and François Englert.
{{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
}}
- Various known composite particles are scalar bosons, e.g. the alpha particle and scalar mesons.
{{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
}}
- The φ4-theory or quartic interaction is a popular "toy model" quantum field theory that uses scalar bosonic fields, used in many introductory quantum textbooks
{{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
}}
{{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.{{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 |url-status=live |access-date=23 May 2021 }}
See also
References
{{reflist|25em}}
{{Particles}}
{{DEFAULTSORT:Scalar Boson}}