Editing Yukawa interaction (section)

{{Short description|Type of interaction between scalars and fermions}}
In [[particle physics]], '''Yukawa's interaction''' or '''Yukawa coupling''', named after [[Hideki Yukawa]], is an interaction between particles according to the [[Yukawa potential]]. Specifically, it is between a [[scalar field (quantum field theory)|scalar field]] (or [[pseudoscalar]] field) <math>\ \phi\ </math> and a [[Dirac field]] <math>\ \psi\ </math> of the type
{{block indent | em = 1.5 | text = <math>~ V \approx g \, \bar\psi \, \phi \, \psi </math>{{pad|1em}} (scalar) {{pad|2em}} or {{pad|2em}}<math> g \, \bar\psi \, i \,\gamma^5 \, \phi \, \psi </math>{{pad|1em}} (pseudoscalar).}}

The Yukawa interaction was developed to model the [[strong interaction|strong force]] between [[hadrons]]. A Yukawa interaction is thus used to describe the [[nuclear force]] between [[nucleon]]s mediated by [[pion]]s (which are pseudoscalar [[meson]]s).

A Yukawa interaction is also used in the [[Standard Model]] to describe the coupling between the [[Higgs field]] and massless [[quark]] and [[lepton]] fields (i.e., the fundamental [[fermion]] particles). Through [[spontaneous symmetry breaking]], these fermions acquire a mass proportional to the [[vacuum expectation value]] of the Higgs field. This Higgs-fermion coupling was first described by [[Steven Weinberg]] in 1967 to model lepton masses.<ref>{{cite journal |last=Weinberg |first=Steven |date=1967-11-20 |title=A Model of Leptons |journal=Physical Review Letters |volume=19 |issue=21 |pages=1264–1266 |doi=10.1103/PhysRevLett.19.1264 | bibcode=1967PhRvL..19.1264W |doi-access=free }}</ref>