Based on a semiclassical expansion for quantum chromodynamics in the
instanton liquid background, the correlation function of the 0++ scalar
glueball current is given, and the properties of the 0++ scalar glueball
are studied in the framework of Gaussian sum rules. Besides the pure classical
and quantum contributions, the contributions arising from the interactions
between the classical instanton fields and quantum gluons are come into play.
Instead of the usual zero-width approximation for the resonance, the
Breit-Wigner form for the spectral function of the finite-width resonance is
adopted. The family of the Gaussian sum rules for the scalar glueball in
quantum chromodynamics with and without light quarks is studied. A consistency
between the subtracted and unsubtracted sum rules is very well justified, and
the values of the decay width and the coupling to the corresponding current for
the 0++ resonance, in which the scalar glueball fraction is dominant, are
obtained.Comment: 18pages, 9figure
