Related papers: Isospin Breaking and Instantons in QCD Nucleon Sum…
The known isospin-breaking contributions to the $K\rightarrow \pi\pi$ amplitudes are reanalyzed, taking into account our current understanding of the quark masses and the relevant non-perturbative inputs. We present a complete numerical…
We propose to increase the factual reliability of descriptions of exotic multiquark hadrons utilizing the approach to bound states of strongly interacting constituents known as QCD sum rules, by allowing exclusively all contributions that…
The quark condensate in nuclear matter contains a term of order $\rho m_\pi$, arising from the contribution of low-momentum virtual pions to the $\pi N$ sigma commutator. Standard treatments of QCD sum rules for a nucleon in matter generate…
QCD sum rules are useful tools for studying the spectral properties of hadrons; however, assumptions underlying standard sum-rule analyses can lead to inconsistencies with known results of chiral perturbation theory. This possibility is…
We study anomalous chiral symmetry breaking in two-flavour QCD induced by gravitational and QCD-instantons within asymptotically safe gravity within the functional renormalisation group approach. Similarly to QCD-instantons, gravitational…
A visible improvement of the QCD sum-rule framework, achieved only recently by a slightly more sophisticated consideration of the hadron excitations and continuum, is applied to the extraction of the decay constants of heavy-light…
Nontrivial topological structures of non-Abelian gauge fields were discovered in the 1970's. Instanton solutions, describing vacuum tunneling through topological barriers, have fermionic zero modes which are at the origin of $^\prime$t…
The QCD sum rule approach is employed in order to study chiral properties of positive- and negative-parity nucleon resonances. It is pointed out that nucleons with an ``exotic'' chiral property, which can be represented by local five-quark…
Motivated by measurements of the flavor singlet axial coupling constant of the nucleon in polarized deep inelastic scattering we study the contribution of instantons to OZI violation in the axial-vector channel. We consider, in particular,…
It is a common belief that the last missing piece of the Standard Model of particles physics was found with the discovery of the Higgs boson at the Large Hadron Collider. However, there remains a major prediction of quantum tunnelling…
We review the recent progress in the applications of QCD sum rules to hadron properties with the emphasis on the following selected problems: (i) development of new algorithms for the extraction of ground-state parameters from two-point…
We consider QCD instanton-induced contributions to lepton pair production in hadron-hadron collisions. We relate these contributions to those known from deep inelastic scattering and demonstrate that they can be calculated reliably for…
The forms of the neutral, non-strange pseudoscalar propagator matrix and mixed axial current correlator, $\lngle0|T(A_\mu^3 A_\nu^8)|0\rangle$, are discussed at next-to-leading (one-loop) order in chiral perturbation theory, and the results…
QCD sum rules for decay constants of heavy mesons with $u$ or $d$ quark yield for $B$ mesons much less isospin breaking than lattice QCD but good agreement for $D$ mesons.
We revisit the large instanton contribution to the gluon Pauli form factor of the constituent quark noted by Kochelev. We check that it contributes sizably to the single spin asymmetry in polarized $p_\uparrow p \rightarrow \pi X$. We use…
We present a study of the QCD interactions which do not conserve the chirality of quarks. These non-perturbative forces are responsible for the violation of the U_A(1) charge conservation and for the breaking of chiral symmetry. From a…
It is shown that the instanton-induced interaction in qq pairs, iterated in t-channel, leads to a meson-exchange interactions between quarks. In this way one can achieve a simultaneous understanding of low-lying mesons, baryons and the…
A new mechanism for single spin asymmetries in strong interaction is proposed. It is based on instanton-induced nonperturbative chromomagnetic quark-gluon interaction. We estimate the contribution of this interaction to single spin…
We construct a model to study the impact of instantons on the low lying eigenvalue spectrum of the Dirac operator. The model is by necessity, approximate, though it does incorporate the important symmetries of the underlying field theory.…
Experimental data on the total cross section of $e^+ e^-$ annihilation into hadrons are confronted with QCD and the operator product expansion using finite energy sum rules. Specifically, the power corrections in the operator product…