Editing Elementary particle (section)

==== Graviton ====

{{Main|Graviton}}

The [[graviton]] is a hypothetical elementary spin-2 particle proposed to mediate gravitation. While it remains undiscovered due to [[Graviton#Experimental observation|the difficulty inherent in its detection]], it is sometimes included in tables of elementary particles.<ref name=PFI /> The conventional graviton is massless, although some models containing massive [[Kaluza–Klein theory|Kaluza–Klein]] gravitons exist.<ref>{{cite journal |arxiv=0910.1535 |bibcode=2010PhLB..682..446C |title=Massless versus Kaluza-Klein gravitons at the LHC |journal=Physics Letters B |volume=682 |issue=4–5 |pages=446–449 |last1=Calmet |first1=Xavier |last2=de Aquino |first2=Priscila |last3=Rizzo |first3=Thomas G. |year=2010 |doi=10.1016/j.physletb.2009.11.045 |hdl=2078/31706|s2cid=16310404 }}</ref>