Related papers: Duality violation in QCD Sum Rules with the LR cor…
The saturation of QCD chiral sum rules of the Weinberg-type is analyzed using ALEPH and OPAL experimental data on the difference between vector and axial-vector correlators (V-A). The sum rules exhibit poor saturation up to current energies…
The operator product expansion of current correlators at short distances, and the notion of QCD-hadron duality are the cornerstone of QCD sum rules. The extension of this programme to $T \neq 0$ is discussed, together with applications to…
QCD sum rules are based on the Operator Product Expansion of current correlators, and on QCD-hadron duality. An extension of this program to finite temperature is discussed. This allows for a study of deconfinement and chiral-symmetry…
The ALEPH data on the vector and axial-vector spectral functions, extracted from tau-lepton decays is used in order to test local and global duality, as well as a set of four QCD chiral sum rules. These are the Das-Mathur-Okubo sum rule,…
To prove the momentum sum rule in the operator product expansion (OPE) in QCD at high energy colliders it is assumed that $<P| {\hat T}^{++}(0)|P>=2(P^+)^2$ where $|P>$ is the momentum eigenstate of the hadron $H$ with momentum $P^\mu$ and…
Quark-hadron duality in the inclusive semileptonic decay $B\to X_c l\nu$ in the Shifman-Voloshin limit $\Lambda \ll \delta m=m_b - m_c \ll m_b, m_c$ is studied within a nonrelativistic potential model. The integrated semileptonic decay rate…
Recent sum rule analyses on the <VV-AA> two-point correlator have led to significant discrepancies in the values found for the OPE condensates, most dramatically in the dimension eight condensate and to a lesser extent in the dimension six…
Interplay between axial anomaly and quark-hadron duality in the presence of strong mixing is considered. The anomaly sum rule for meson transition form factors based on the dispersive representation of axial anomaly and quark-hadron duality…
Using the updated ALEPH V-A spectral function from tau decays, we determine the lowest spectral moments of the left-right correlator and extract dynamical information on order parameters of the QCD chiral symmetry breaking. Uncertainties…
While the idea of using the operator product expansion (OPE) to extract the strong coupling from hadronic $\tau$ decay data is not new, there is an ongoing controversy over how to include quark-hadron "duality violations" (i.e., resonance…
We study the operator product expansion (OPE) and quark-hadron duality for 2- and 3-point correlators of the axial (A) and pseudoscalar (P) currents of the light quarks. In the chiral limit these correlators are often dominated by…
Dispersive sum rules constitute long-standing tools for extracting hadron features from QCD. We estimate the systematic uncertainties induced by assuming quark-hadron duality and improve the accuracy of the resulting predictions by…
We identify conditions under which a summation over nucleon resonances can yield, via quark-hadron duality, parton model results for electromagnetic and neutrino structure functions at large x. While a summation over the lowest even and odd…
We point out that naive pentaquark correlations function include two-hadron-reducible contributions, which are given by convolution of baryon and meson correlation functions and have nothing to do with pentaquark. We show that the…
Several different analysis methods have been developed to determine the strong coupling via finite-energy sum-rule analyses of hadronic $\tau$ decay data. While most methods agree on the existence of the well-known ambiguity in the choice…
We study details of QCD sum rules \`a la Shifman-Vainshtein-Zakharov for exotic tetraquark states. We point out that duality relations for correlators involving exotic currents have fundamental differences compared with the duality…
We use the procedure of pinched-weight Finite Energy Sum Rules (pFESR) to determine the OPE coefficients a_6, ...,a_16 of the flavor ud V-A correlator in terms of existing hadronic tau decay data. We show by appropriate weight choices that…
We perform numerical analysis of double-pinched Borel-Laplace QCD sum rules for the strangeless semihadronic $\tau$-decay data. The $D=0$ contribution to the theoretical contour integral in the sum rules is evaluated by the (truncated)…
The presence of terms that violate quark-hadron duality in the expansion of QCD Green's functions is a generally accepted fact. Recently, a new approach was proposed for the study of duality violations (DVs), which exploits the existence of…
We construct QCD sum rules for nonperturbative studies without assuming the quark-hadron duality for the spectral density at low energy on the hadron side. Instead, both resonance and continuum contributions to the spectral density are…