相关论文: Duality violations and spectral sum rules

We analyze new QCD sum rules for the pion wave function $\phi_{\pi}(x)$, obtained recently by A.V. Radyushkin in the framework of the non-local vacuum condensates method for non-diagonal correlators, and suggest a new approach for…

Non-relativisitic second-order corrections to the wave function at origin in muonic and exotic atoms are considered. The corrections are due to the electronic vacuum polarization. Such corrections are of interest due to various effective…

The Coleman-Glashow sum-rule for magnetic moments is always fulfilled in the chiral quark model, independently of SU(3) symmetry breaking. This is due to the structure of the wave functions, coming from the non-relativistic quark model.…

The non-zero Dirac phases $\delta^q$ and $\delta^l$ in the CKM and PMNS mixing matrices signify CP violation. In general they are independent. Experimental data including recent T2K results show, however, that in the original KM…

We use the operator product expansion (OPE) to show that non-perturbative QCD corrections to $\Delta\rho$ can be calculated using unsubtracted dispersion relations for either the transverse or the longitudinal vacuum polarization functions.…

In QCD sum rules with external fields, the double dispersion relation is often used to represent the correlation function. In this work, we point out that the double spectral density, when it is determined by successive applications of the…

The anomalous <VVP> Green function and related form-factors (pi^0 to gamma^* gamma^* and tau^- to X^- nu_tau vector form-factors, with X^-=(KKpi)^-, phi^- gamma, (phi V)^-) are analyzed in this letter in the large-N_C limit. Within the…

We point out that, contrary to existing claims of the opposite, Vainshtein's theorem on the non-renormalization of the correlator of an axial and two vector currents, is only valid in the chiral limit. When quarks, that contribute to the…

We perform a finite energy sum rule analysis of the flavor ud two-point V-A current correlator, Delta Pi (Q^2). The analysis, which is performed using both the ALEPH and OPAL databases for the V-A spectral function, Delta rho, allows us to…

Within the framework of a general non-linear effective field theory describing the electroweak symmetry breaking, we perform a detailed analysis of the next-to-leading contributions to the electroweak oblique parameters $S$ and $T$ from…

We analyze the heavy quark bound state spectrum using an order-dependent conformal mapping to re-sum the perturbative expansion for current correlators. The procedure consists of two main steps. Firstly, the Borel plane structure of the…

We consider the two-fold expansion in powers of the conformal anomaly and of the strong coupling $\alpha_s$ for the non-singlet contributions to Adler $D$-function and Bjorken polarized sum rule calculated previously in the $\MSbar$-scheme…

Hadronic tau decay data is used to study the reliability of various finite energy sum rules (FESR's). For intermediate scales (of order 2-3 GeV^2), those FESR's with weights s^k are found to have significant errors, whereas those with…

The chiral symmetry of QCD is studied at finite temperature and chemical potential using the Schwinger-Dyson equation in the improved ladder approximation. We calculate three order parameters; the vacuum expectation value of the quark…

A classic sum rule by Das et al. is extended to seven of the low-energy constants $K_i$, introduced by Urech, which parameterize electromagnetic corrections at chiral order $O(e^2p^2)$. Using the spurion formalism, a simple convolution…

The conformal algebra provides powerful constraints, which guarantee that renormalized conformally covariant operators exist in the hypothetical conformal limit of the theory, where the $\beta$-function vanishes. Thus, in this limit also…

We explore the implications of recent results relating the Dirac CP-violating phase to predicted and measured leptonic mixing angles within a standard set of theoretical scenarios in which charged lepton corrections are responsible for…

The consideration of chirality-preserving 2-fermion order parameters may shed new light on the strong CP problem and the breakdown of flavor symmetries. We describe two situations, one having the standard KM picture for weak CP violation…

Since order parameter of the chiral symmetry breaking Green Functions are a useful link between the OPE expansion and chiral perturbation theory we perform a calculation to the NLO in alpha_s, working in the chiral limit, for all the 2 and…

It was recently conjectured that, in SU(3) gauge theories with fundamental quarks, valence spontaneous chiral symmetry breaking is equivalent to condensation of local dynamical chirality and appearance of chiral polarization scale…