DOI 10.1007/s100520000254
Gluon field strength correlation functions
within a constrained instanton model
A.E. Dorokhov1,2 - S.V. Esaibegyan1,3 - A.E. Maximov1 - S.V. Mikhailov1
1 Joint Institute for Nuclear Research,
Bogoliubov Laboratory of Theoretical Physics,
141980, Moscow Region, Dubna, Russia
2 Instituto de Fisica Teorica, UNESP,
Rua Pamplona, 145, 01405-900, Sao Paulo, Brazil
3 Yerevan Physics Institute, 375036, Yerevan, Armenia
Received: 18 June 1999 / Revised version: 21 July 1999 /
Published online: 17 February 2000 - © Springer-Verlag
2000
Abstract
We suggest a constrained instanton (CI) solution in the physical
QCD vacuum
which is described by large-scale vacuum field fluctuations.
This solution
decays exponentially at large distances. It is stable only if
the
interaction of the instanton with the background vacuum field
is small and
additional constraints are introduced. The CI solution is explicitly
constructed in the ansatz form, and the two-point vacuum correlator
of the gluon
field strengths is calculated in the framework of the effective
instanton
vacuum model. At small distances the results are qualitatively
similar to
the single instanton case; in particular, the D1 invariant
structure is
small, which is in agreement with the lattice calculations.
Copyright Società Italiana di Fisica, Springer-Verlag 2000
