Improved Effective Action for Light Quarks Beyond Chiral Limit

We propose an improvement of the Diakonov-Petrov Effective Action on the basis of the Lee-Bardeen results for the quark determinant in the instanton field. This Improved Effective Action provides proper account of the current quark masses, which is particularly important for strange quarks. This Action is successfully tested by the calculations of the quark condensate, the masses of the pseudoscalar meson octet and by axial-anomaly low-energy theorems.Comment: 15 pages, 1 figure, Latex. New references were adde

Current mass dependence of the quark condensate and the constituent quark mass

We discuss the current mass dependence of the basic quantities of the quark models -- constituent quark mass M and quark condensate i. The framework of the consideration is QCD instanton vacuum model.Comment: 7 pages, 2 figures, talk presented at the International Symposium on Hadrons and Nuclei, Seoul, February 20-22, 200

Heavy and light quarks in the instanton vacuum

Assuming the gluon field is well approximated by instanton configurations we derive a light quarks determinant and calculate its contribution to the specific heavy quarks correlators -- namely, the heavy quark propagator and heavy quark-aniquark correlator, receiving the instanton generated light-heavy quarks interaction terms contributions. With these knowledge we calculate the light quark contribution to the interaction between heavy quarks, which might be essential for the properties of a few heavy quarks systems.Comment: Talk given at the workshop "Hadron Nuclear Physics 2011", APCTP, Pohang, Republic of Korea, Feb. 21-24, 2011. The workshop proceedings will be published at the EPJ web of conferences (http://www.epj-conferences.org/

Heavy-heavy and heavy-light quarks interactions generated by QCD vacuum

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