The QCD vacuum is populated by instantons that correspond to the tunneling
processes in the vacuum. This mechanism creates the strong vacuum gluon fields.
As result, the QCD vacuum instantons induce very strong interactions between
light quarks, initially almost massless. Such a strong interactions bring a
large dynamical mass M of the light quarks and bound them to produce almost
massless pions in accordance with the spontaneous breaking of the chiral
symmetry (SBCS). On the other hand, the QCD vacuum instantons also interact
with heavy quarks and responsible for the generation of the heavy-heavy and
heavy-light quarks interactions, with a traces of the SBCS. If we take the
average instanton size \rho=0.33 fm, and the average inter-instanton distance
R=1 fm we obtain the dynamical light quark mass to be M = 365 MeV and the
instanton media contribution to the heavy quark mass \Delta M=70 MeV. These
factors define the coupling between heavy-light and heavy-heavy quarks induced
by the QCD vacuum instantons. We consider first the instanton effects on the
heavy-heavy quarks potential, including its spin-dependent part. We also
discuss those effects on the masses of the charmonia and their hyperfine mass
splittings. At the second part we discuss the interaction between a heavy and
light quarks generated by instantons and it's effects.Comment: XIIth Quark Confinement and the Hadron Spectrum, 28 Aug.2016-4
Sept.2016, Thessaloniki (Greece), invited talk, 9 page
