QCD sum rules
Encyclopedia
In quantum chromodynamics
, the confining and strong coupling nature of the theory means that conventional perturbative techniques often fail to apply. The QCD sum rules (or Shifman
–Vainshtein–Zakharov sum rules) are a way of dealing with this. The idea is to work with gauge invariant operators and operator product expansion
s of them. The vacuum to vacuum correlation function for the product of two such operators can be reexpressed as
where we have inserted hadronic particle states on the right hand side.
Quantum chromodynamics
In theoretical physics, quantum chromodynamics is a theory of the strong interaction , a fundamental force describing the interactions of the quarks and gluons making up hadrons . It is the study of the SU Yang–Mills theory of color-charged fermions...
, the confining and strong coupling nature of the theory means that conventional perturbative techniques often fail to apply. The QCD sum rules (or Shifman
Mikhail Shifman
-External links:*****...
–Vainshtein–Zakharov sum rules) are a way of dealing with this. The idea is to work with gauge invariant operators and operator product expansion
Operator product expansion
- 2D Euclidean quantum field theory :In quantum field theory, the operator product expansion is a Laurent series expansion of two operators...
s of them. The vacuum to vacuum correlation function for the product of two such operators can be reexpressed as
where we have inserted hadronic particle states on the right hand side.