Related papers: Chiral sum rules and vacuum condensates from tau-l…
Recent developments in the evaluation of vector-meson spectral functions in hot and dense matter are discussed with emphasis on connections to the chiral phase transition in QCD. Model independent approaches including chiral low-density…
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…
In this article, we recalculate the contributions of all vacuum condensates up to dimension-6, in particular the one-loop corrections to the quark condensates $\alpha_s<\bar{q}q>$ and partial one-loop corrections to the four-quark…
We develop a number of sum rules comparing spectral integrals involving judiciously chosen weights to integrals over the corresponding Euclidean two-point function. The applications we have in mind are to the hadronic vacuum polarization…
We propose a phenomenological QCD sum rule with an explicit diquark field to investigate the essential ingredients inside the hadrons. Introducing the mass (m_\phi) and the condensate (\phi^2) for the diquark field as parameters in the…
We select sum rules from which one can extract directly reliable limits on the size of the chiral symmetry breaking light quark condensate $<\bar\psi\psi>$. Combined results from the nucleon and $B^*-B$ mass-splitting sum rules give a…
We study a functional method to extract the V-A condensate of dimension 6 from a comparison of tau-decay data with the asymptotic space-like QCD prediction. Our result is in agreement within errors with that from conventional analyses based…
We use results of fits to the OPAL spectral data, obtained from non-strange hadronic \tau decays, to evaluate the difference between the vector and axial current correlators, \Pi_{V-A}(Q^2). The behavior of \Pi_{V-A}(Q^2) near euclidean…
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…
We derive four sum-rule expressions for spectra measured in electron energy-loss near edge structure experiments. These sum-rules permit the determination spin and orbital magnetic moments, spin-orbit interaction and number of states,…
A new QCD calculation of the mass of the nucleon is presented. It makes use of a polynomial kernel in the dispersion integrals tailored to practically eliminate the contribution of the unknown 1=2+ and 1=2- continuum. This approach avoids…
We study two and three meson decays of the tau lepton within the framework of the Resonance Chiral Theory, that is based on the following properties of QCD: its chiral symmetry in the massless case, its large-N_C limit, and the asymptotic…
QCD sum rules are analytic predictions of hadron observables from quantum chromodynamics. In the so-called local-duality limit of their Borel-transformed form, all nonperturbative contributions are encompassed by just a single quantity, an…
We shortly review some applications of the (inverse) Laplace (LSR) transform sum rules in Quantum ChromoDynamics (QCD) for extracting the fundamental QCD parameters (coupling constant $\alpha_s$, quark and gluon condensates) and the hadron…
Recently the \mu_{\Delta ^{++}} was found from a fit to (\pi^+)p scattering. This enable us to pinpoint condensate parameters more precisely in the context of QCD sum rules (QCDSR). In the octet sector, the Coleman-Glashow sum rule (CGSR)…
Chiral perturbation theory at finite four-volume V (=L^3T) is reconsidered with a view towards finding a computational scheme that can deal with any value of M_\pi L, where M_\pi is a generic Nambu-Goldstone mass. The momentum zero modes…
The current theoretical status in the analysis and interpretation of low-mass dilepton measurements in (ultra-) relativistic heavy-ion experiments is reviewed. Special emphasis is put on potential signals of (partial) restoration of…
The gap Delta = 4 pi f_pi ~ 1.2 GeV of spontaneous chiral symmetry breaking is introduced as a scale delineating resonance and continuum regions in the QCD spectral sum rules for vector mesons. Basic current algebra results are easily…
We derive thermal QCD sum rules for the correlation function of two vector currents in the rho-meson channel. It takes into account the leading non-perturbative corrections from the additional operators, which appear due to the breakdown of…
We study chiral symmetry breaking using the quark gap equation supplemented with the infrared-finite gluon propagator and ghost dressing function obtained from large-volume lattice simulations. One of the most important ingredients of this…