Editing Strangeness (section)

{{Short description|Property of elementary particles}}
{{About||the 2022 Italian comedy film|Strangeness (film)}}
{{see also|Strangeness and quark–gluon plasma}}
{{Flavour_quantum_numbers}}
In [[particle physics]], '''strangeness''' (symbol '''''S''''')<ref>{{Cite book|last=Jacob|first=Maurice|url=https://www.worldscientific.com/worldscibooks/10.1142/1653|title=The Quark Structure of Matter|publisher=World Scientific|year=1992|isbn=978-981-02-0962-9| series=World Scientific Lecture Notes in Physics|volume=50|language=en|doi=10.1142/1653}}</ref><ref>{{Cite journal| last1=Tanabashi|first1=M.|last2=Hagiwara|first2=K.|last3=Hikasa|first3=K.|last4=Nakamura|first4=K.|last5=Sumino|first5=Y.|last6=Takahashi|first6=F.|last7=Tanaka|first7=J.|last8=Agashe|first8=K.|last9=Aielli|first9=G.|last10=Amsler|first10=C.|last11=Antonelli|first11=M.|date=2018-08-17|title=Review of Particle Physics|journal=Physical Review D|language=en|volume=98|issue=3|page=030001 |doi=10.1103/PhysRevD.98.030001|pmid=10020536|bibcode=2018PhRvD..98c0001T|issn=2470-0010|quote=pages 1188 (Mesons), 1716 ff (Baryons)|doi-access=free|hdl=10044/1/68623|hdl-access=free}}</ref> is a [[Physical property|property]] of [[Particle|particles]], expressed as a [[quantum number]], for describing [[Particle decay|decay]] of particles in [[Strong interaction|strong]] and [[Electromagnetic interaction|electromagnetic interactions]] that occur in a short period of [[time]]. The strangeness of a particle is defined as:
<math display="block">S = -(n_\text{s} - n_{\bar{\text{s}}})</math>
where ''n''<sub>{{SubatomicParticle|Strange quark}}</sub> represents the number of [[strange quark]]s ({{SubatomicParticle|Strange quark}}) and ''n''<sub>{{SubatomicParticle|Strange antiquark}}</sub> represents the number of [[strange antiquark]]s ({{SubatomicParticle|Strange antiquark}}). Evaluation of [[strangeness production]] has become an important tool in search, discovery, observation and interpretation of [[quark–gluon plasma]] (QGP).<ref>{{Cite journal|last1=Margetis|first1=Spyridon|last2=Safarík|first2=Karel|last3=Villalobos Baillie|first3=Orlando|year=2000|title=Strangeness Production in Heavy-Ion Collisions|journal=[[Annual Review of Nuclear and Particle Science]]|language=en|volume=50|issue=1|pages=299–342|doi=10.1146/annurev.nucl.50.1.299|doi-access=free| bibcode=2000ARNPS..50..299S|issn=0163-8998}}</ref> Strangeness is an excited state of matter and its decay is governed by [[Cabibbo–Kobayashi–Maskawa matrix|CKM mixing]]. 

The terms ''strange'' and ''strangeness'' predate the discovery of the quark, and were adopted after its discovery in order to preserve the continuity of the phrase: strangeness of particles as −1 and anti-particles as +1, per the original definition. For all the quark flavour quantum numbers (strangeness, [[charm (quantum number)|charm]], [[topness]] and [[bottomness]]) the convention is that the flavour charge and the electric charge of a quark have the same sign. With this, any flavour carried by a charged [[meson]] has the same sign as its charge.